It has a lot of validity. Your main argument is that the word "To'evah" appears only in the context of worship of other gods, and it certainly does so in many places - Ezekiel uses it exclusively for this context.

And yet it is used just to mean "abomination" - e.g., in Proverbs. This is certainly its meaning in modern Hebrew.

What mainly bothers me, though, is the fact that anybody can find anything in the Bible. You can always find an interpretation that fits your purpose. I suspect this is the reason why the bible is said to "encompass everything".

If you look at the various decrees in Leviticus and other places, you may reach a totally different conclusion: that the author of the bible mostly abhors sexual acts that waste semen, or that make parentage complicated. So Onan is punished for wasting his semen. And here in Leviticus a man is forbidden from laying with another man, and with beasts, and with a menstruating woman.

Notice that a man is forbidden from laying with another man - but a woman is not, as this wastes no semen. Semen is viewed as something magical, carrying mystical powers.

I believe my arguments here are as strong as yours, but my conclusion contradicts yours: that the bible forbids homosexuality in men.

What it all boils down to is that we both have supporting evidence, and almost everybody can find supporting evidence and use creative interpretation. Sometimes, alas, this interpretation is used for less benign ends than just reconciling one's religious feelings with ones lifestyle. This is true, I believe, for every collection of scriptures. Heck, we use these tricks with modern-day constitutions as well.

Disclaimer: I am not a Christian and do not come from a Christian background. Do not deduce from the above that I oppose homosexuality - the Bible has no authority over me, even if my interpretation is the "right" one. I believe there is no "right" intepretation of the bible.