I would answer your question/questions this way. The book is framed by Paul by basically asking the question who is going to lead us? The Spirit through Christ, or the Law through flesh? It is one or the other, they are mutually exclusive (Romans 11:6 And if by grace, then is it no more of works: otherwise grace is no more grace. But if it be of works, then is it no more grace: otherwise work is no more work.) and operate by different paradigms.
It is key to view your question through more of the passage than just a few verses. He says:
Galatians 5:16-26 "This I say then, Walk in the Spirit, and ye shall not fulfill the lust of the flesh. For the flesh lusts against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that you would. But if you be led of the Spirit, you are not under the law."
Notice the contrasts mentioned. Spirit verses flesh. Spirit verse Law. Now he gives a general overview of what flesh, if left to its own devices, goes for:
Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness, Idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies, Envying's, murders, drunkenness, reveling, and such like:
of the which I tell you before, as I have also told you in times past, that they which do such things shall not inherit the kingdom of God.
It's not like we have no standards at all, we have moved from law to the giver of the law, Christ himself. Not a lesser standard, but a different one.
But he doesn't stop there. He is using that as a furtherance of his argument of flesh/law verses Spirit/Christ for dominion. He goes on to contrast that list with the other one when he says:
But the fruit of the Spirit is **love, joy, peace, longsuffering, gentleness, goodness, faith, Meekness, temperance: *against such there is no law*.**
So, here Spirit fruit is contrasted with law again. Then he gets to his point, he says:
And they that are Christ's have crucified the flesh with the affections and lusts. If we live in the Spirit, let us also walk in the Spirit.
It is a done deal, flesh/law is done, now we are under Christ/Spirit leading...so we should walk like it.
The point is, those who do those horrible things will not go to heaven because the assumption is that those people who do those things are still in the flesh following after the Law rather than being in the Spirit following after Christ ("Romans 8:9:But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his."). The book is set up to deal with the idea of a Christian going back under the law after coming to Christ.