>Do you see them as a problem?
No, like autists and down syndrome people, these guys are also a great challange for us that we must learn to overcome in love. Loving these people is harder, but it is still a worthy goal.
>Is it a mental illness?
Maybe but I don't see how it's relevant. It is their cross to bear no matter what it is. I don't know if God is more merciful with mentally ill people but I kinda hope so.
>Is it learned behaviour?
No. All research seems to refute this. Homosexuals genuinely feel attracted to their own gender, and they don't need education to develop these tendencies.
>If it's sinful, why doesn't Jesus ever talk on the issue?
Well I don't know. There are lots of theories about this, but even if we agree that homosexuality is not a sin, sex outside of marriage still is a sin, and marriage is between a man and a woman for the purpose of procreation and the regulation of sex in society.
>Is it actually a sin, or is it a sin only because sex outside of marriage is sin, and two men can't get married?
It's a sin because two men can't get married (and yes it's an invalid marriage even if someone were to perform such a ceremony)
>Is it possible for two homosexuals to have real love between them instead of pure lust?
Most certainly, but it's definitely a rarity. Gay stereotypes for the most part, are true.
>If so, is that love valuable?
All love is valuable. So is beauty, so is truth. But I'm not entirely sure that our understanding of love can ever be complete. I hope though.
>What is the line that shouldn't be crossed? Hugs? Kisses? Anal sex?
Hugs and kissing are fine. Sexual acts are where the sin lies, because in principle, sex has a function other then expressing affection and love, namely, making babies, and if you exclude the possibility of creating a baby with your sexual act, you separate sex from it's function. As long as your love is disinterested, as in, you express your love without expecting anything in return, I think that showing affection is fine, be it hugs, or kisses. However, please understand that hugs and kisses are not neccessary for love to thrive, nor is sex. Hugs and kissing are fine because their very purpose is the expression of love towards another.
BUT it IS a slippery slope (and that is not a fallacy).
>What should be done with them? Execution? Banishment? Rehabilitation?
We should, as a society find a way to help them, and treat this issue as openly and transparently as possible. Removing the stigma would be good for a more honest and open treatment of the issue, because that would allow us to work with these people. In any case, we must break down their cliques and destroy their "culture". Gay culture should not exist and it shouldn't be celebrated.
Also, we must develop a treatment/cure/lifestyle for them that they can follow in a way that allows them to have standing as citizens with dignity. And we must help them acknowledge that they shouldn't be the norm. This is possibly the hardest part, and it's the main source of conflict.