Is it possible to receive the full effects of the Catholic Spiritual Communion if one is being distanced from the Communion due to being gay?
That will depend on the interior disposition of the individual at that time!
How to benefit from the in the fullest sense from making a Spiritual Communion.
When Catholics are properly disposed to receive Our Lord in the Sacred Host at Mass, but are impeded for one reason or another, they can always make a Spiritual Communion in it’s place. Thus receiving the same graces as going to actual Holy Communion.
Our souls must likewise be prepared as if going to Holy Communion at Mass. We must be in the State of Grace!
Any extramarital sexual activities thus must be confessed to a priest prior to receiving Holy Communion. If one is ill dispensed to receive the Sacrament of the Altar, then one is also ill dispense to receive any graces in a Spiritual Communion.
I am thinking that your quote from Wikipedia is in error as to what the Church clearly teaches on the subject on a Spiritual Communion. Here is what the CDF wrote about this subject matter in 1983:
Individual faithful or communities who because of persecution or lack of priests are deprived of the holy Eucharist for either a short or longer period of time, do not thereby lack the grace of the Redeemer. If they are intimately animated by a desire for the sacrament and united in prayer with the whole Church, and call upon the Lord and raise their hearts to him, by virtue of the Holy Spirit they live in communion with the whole Church, the living body of Christ, and with the Lord himself. Through their desire for the sacrament in union with the Church, no matter how distant they may be physically, they are intimately and really united to her and therefore receive the fruits of the sacrament; whereas those who would wrongly attempt to take upon themselves the right to confect the Eucharistic Mystery end up by having their community closed in on itself. - Letter to Bishops of the Catholic Church on Certain Questions concerning the Minister of the Eucharist
Thus it is clear that in order to make a Spiritual Communion effective, Catholics must make it with the same interior dispositions as if going to receive Holy Communion.
Fish eaters explains the notion of Spiritual Communion in a very readable way:
We are obliged to attend Mass each Sunday and on every other Holy Day of Obligation. Sometimes, though, we just can't be there. One's own sickness or the obligations to care for a sick person, having given birth within the past 6 weeks, dangerous weather (and other safety hazards), not being able to find a way there -- life happens. There is no guilt in missing Mass if the circumstances are out of one's control (mortal sin always requires not only grave matter and knowledge, but consent of the will).
And sometimes, there is no Mass readily-enough available. The rule of thumb concerning Mass availability is that if one is required to travel more than an hour to reach a Mass, one is not guilty of sin by not attending.
In all these instances, we are encouraged to make what is known as a "spiritual Communion," an act expressing what was described by St. Thomas Aquinas as "an ardent desire to receive Jesus in the Most Holy Sacrament and in lovingly embracing Him." In a spiritual Communion, we, with contrite, humble hearts, ask our Lord to come to us in the same way He would if we were able to receive the Sacrament. This can be done as often as one likes, informally in one's own words or through one of the traditional prayers which appear below.
What is the value of this practice? The graces received may be as great as -- or greater than -- those received by some people in the actual Sacrament. Though, of course, the Sacrament itself is inherently greater, our disposition toward the Sacrament affect whether and how we receive its fruits. For example, imagine a woman who is unable to be with her husband but who desires him as contrasted with a woman who has her husband's presence but doesn't care for him. Which husband would be more apt to pour out his love for his wiffe?
How to Receive Spiritual Communion
St. Leonard of Port-Maurice offers this advice for receiving Spiritual Communion:
In order to facilitate a practice of such great excellence, ponder what I have to say. When the priest is about to give himself Communion in holy Mass, do you, keeping composed externally and internally, excite in your heart an act of true contrition, and humbly striking your breast, in token that you acknowledge yourself unworthy of so great a grace, make all those acts of love, of self-surrender, of humility, and the rest, which you are accustomed to make when you communicate sacramentally, and then desire with a lively longing to receive your good Jesus, veiled in the sacrament for your benefit. And to kindle your devotion, imagine that most holy Mary, or some saint, your holy advocate, is holding forth to you the sacred particle; figure yourself receiving it, and then, embracing Jesus in your heart, reply to Him, over and over again, with interior words prompted by love: “Come, Jesus, my Beloved, come within this my poor heart; come and satiate my desires; come and sanctify my soul; come, most sweet Jesus, come!” This said, be still; contemplate your good God within you, and, as if you really had communicated, adore Him, thank Him, and perform all those interior acts to which you are accustomed after sacramental Communion.
Here is a choice of a few different formal prayers to pray while following St. Leonard's advice, though you can pray in your own words, if you prefer:
Act of Spiritual Communion by St. Alphonsus Liguori (A.D. 1696-1787)
My Jesus, I believe that Thou art present in the Blessed Sacrament. I love Thee above all things and I desire Thee in my soul. Since I cannot now receive Thee sacramentally, come at least spiritually into my heart. As though thou wert already there, I embrace Thee and unite myself wholly to Thee; permit not that I should ever be separated from Thee.
Act of Spiritual Communion
O Immaculate Queen of Heaven and Earth, Mother of God and Mediatrix of every grace: I believe that Thy dearly beloved Son, Our Lord Jesus Christ, is truly, really, and substantially contained in the Most Blessed Sacrament. I love Him above all things and I long to receive Him into my heart. Since I cannot now receive Him sacramentally, be so good as to place Him spiritually in my soul.
O my Jesus, I embrace Thee as One who has already come, and I unite myself entirely to Thee. Never permit me to be separated from Thee. Amen.
Act of Spiritual Communion
As I cannot this day enjoy the happiness of assisting at the holy Mysteries, O my God! I transport myself in spirit at the foot of Thine altar; I unite with the Church, which by the hands of the priest, offers Thee Thine adorable Son in the Holy Sacrifice; I offer myself with Him, by Him, and in His Name. I adore, I praise, and thank Thee, imploring Thy mercy, invoking Thine assistance, and presenting Thee the homage I owe Thee as my Creator, the love due to Thee as my Savior.
Apply to my soul, I beseech Thee, O merciful Jesus, Thine infinite merits; apply them also to those for whom I particularly wish to pray. I desire to communicate spiritually, that Thy Blood may purify, Thy Flesh strengthen, and Thy Spirit sanctify me. May I never forget that Thou, my divine Redeemer, hast died for me; may I die to all that is not Thee, that hereafter I may live eternally with Thee. Amen.
Missing Mass & Spiritual Communion
Only mortal sins that have not been sacramentally confessed and absolved in the sacrament of confession can keep one away from receiving Our Savour in Holy Communion. If we are ill disposed in the first, we will be ill disposed in the second.
Being gay does not inherently mean we can not receive Holy Communion; providing that one lives a pure and chaste life. For those who have fallen into serious sexual sin there is always confession. Humility is always the first step in the spiritual life.