Asking if “this [hallal] meat is being offered up to idols” seems to me a similar question as asking whether islam is idolatry (from a Catholic point of view).
What is idolatry?
A longer discussion of this definition can be found in the Dictionnaire de Théologie Catholique (“IDÔLATRIE
”). The Church Fathers understand idolatry as a worship rendered to false gods (Clement of Alexandry, St Gregory of Nazianzus). Origen is more precise and distinguishes the image (είκων) – true representation of an existing thing – from the idol (εἴδωλον) – false representation of a thing that doesn’t exist.
This sense is also the one of the Holy Scriptures (if you need more details about it please see the little bibliography at the end of my answer). That’s why idolatry must be defined as (translation of the formulation by F. Prat, Dictionnaire de la Bible, at “IDÔLE
”):
The supreme and absolute cult rendered to any other than the unique and true God.
So the question is: (according to Catholic Church) do they render a cult to the true God?
Is the Allah of Islam the same as the God of Christians?
According to Athanase Creed (recited by Catholics at Prime on Sunday, and admitted by Protestants), “the Father is God, the Son is God, and the Holy Spirit is God, and yet there are not three Gods but one God” (Ita Deus Pater, Deus Filius, Deus [et] Spiritus Sanctus. Et tamen non tres dii, sed unus est Deus).
All human have the same God, in the sense that He is our Creator, whereas it doesn’t mean that all humans believe in Him: any God that isn’t triune is not the true God of Christians.
Even if they are right to be monotheistic, Muslims believe (ShahadaW):
There is no god but God. Muhammad is the messenger of God.
And in fact Muslims oppose with force and sometimes violence against Christians precisely because of the trinitarian dogma. That’s why it remains clear that, from a Catholic point of view, they worship an idol that they name Allah and that isn’t the triune God.
Hallal meat
So now is hallal meat being offered up to Allah? It seems so: according to Wikipedia:
Dhabīḥah (or zabiha, Arabic: ذَبِيْحَة dhabīḥah IPA: [ðæˈbiːħɐ], 'slaughter'(noun)) is, in Islamic law, the prescribed method of ritual slaughter of all lawful halal animals (goats, sheep, cows, chicken) excluding locusts, fish, and most sea-life. Unlawful animals like pigs, dogs, lions, bears, etc. are not allowed to be slaughtered or zabihah. This method of slaughtering lawful animals has several conditions to be fulfilled. The butcher must be Muslim, the name of God or "In the name of God" (Bismillah) must be called by the butcher upon slaughter of each halal animal separately, and it should consist of a swift, deep incision with a very sharp knife on the throat, cutting the wind pipe, jugular veins and carotid arteries of both sides but leaving the spinal cord intact.
Dhabihah
What we have demonstrated is that, according to a catholic definition of idolatry and to the fundamental differences between Islamic Allah and catholic dogmas about what is God, Allah is in fact an idol from a catholic point of view.
Furthermore, it seems that dhabīḥah is a sacrifice to this Allah. So we may say: “Yes, hallal meat is being offered up to idol.”
From a Catholic point of view, it is meat sacrificed to idols, and so 1 Cor 10, 2 Cor 6, Acts 15:28–29… could be applied to hallal meat. By the way, this answer isn’t exactly an answer of the Catholic Church as it seems that no text of the Magisterium specifically deals with halal meat (and I personally find it logical): this answer is only an argumentation build on what the Catholic Church teaches.
As a conclusion, this interesting commentary of Blessed Innocent V on 1 Cor 10:28–32 (usually included in Saint Thomas Aquinas commentaries, translation by the Aquinas Institute):
If I partake with thanksgiving, why am I spoken ill of for that for
which I give thanks? [n. 568]
Above he warned them to beware eating the food of idols, and he has
given four reasons for his admonition: here he teaches, third, the way
to beware the abovementioned things, by showing how one is allowed to
eat, and how not.
First therefore he shows whether it is licit to eat;
second, when it is not licit, at but if any man says;
third, what to attend to in either case at therefore, whether you eat
(1 Cor 10:31).
read more…
Bibliography
On the definition of idolatry
- Dictionnaire de Théologie Catholique, “
IDÔLATRIE
”
On the sense of idolatry in the Holy Scriptures
- Dictionnaire de Théologie Catholique, “
IDÔLATRIE
”
- F. Prat, Dictionnaire de la Bible, “
IDÔLE
”
- Hagen, Lexicon biblicum, the definition of the word “
[IDOLOLATRIA][2]
”
Commentaries on Aquinas
In addition: some exact references to the teaching of Catholic Church
Believing in God cannot be separated from believing in the One he sent, his ‘beloved Son’
For a Christian, believing in God cannot be separated from believing in the One he sent, his ‘beloved Son’, in whom the Father is ‘well pleased’; God tells us to listen to him. The Lord himself said to his disciples: ‘Believe in God, believe also in me’ (Jn 14:1). We can believe in Jesus Christ because he is himself God, the Word made flesh: ‘No one has ever seen God; the only Son, who is in the bosom of the Father, he has made him known’ (Jn 1:18). Because he ‘has seen the Father’, Jesus Christ is the only one who knows him and can reveal him (Jn 6:46; cf. Mt 11:27). (Catechism of the Catholic Church, no. 151)
Islam denies that Christ is truly the Son of God
He [Mohammed] says that the Christ is the Word of God and His Spirit, but a creature and a servant, and that He was begotten, without seed, of Mary the sister of Moses and Aaron. For, he says, the Word and God and the Spirit entered into Mary and she brought forth Jesus, who was a prophet and servant of God. (St John Damascene, Concerning Heresies, 101: PG 94, 766)
First of all we must observe that Muslims are silly in ridiculing us for holding that Christ is the Son of the living God, as if God had a wife. Since they are carnal, they can think only of what is flesh and blood. For any wise man can observe that the mode of generation is not the same for everything, but generation applies to each thing according to the special manner of its nature. […] So generation should be understood of God as it applies to an intellectual nature. (St Thomas Aquinas, Compendium on Reasons for the Faith against Muslim Objections, 3)
O People of the Book, exceed not the limits in your religion, and say not of Allah anything but the truth. Verily, the Messiah, Jesus, son of Mary, was only a Messenger of Allah and a fulfilment of His word which He sent down to Mary, and a mercy from Him. So believe in Allah and His Messengers, and say not ‘They are three.’ Desist, it will be better for you. Verily, Allah is the only One God. Far is it from His Holiness that He should have a son. To Him belongs whatever is in the heavens and whatever is in the earth. And sufficient is Allah as a Guardian.
(Koran 4:172)