Nor must it be. There is nothing inherently immoral about homosexuality.
Um... yes there is, and morality aside there are many heath risks associated with it.
Now. If you would stop spouting your disgusting bile for a second, could you please try and show us why exactly homosexuality is harmful to society or immoral without referring to your homicidal Holy Book?
Um... show me why homosexuality should be encouraged, in light of its health risks etc.
Simply because it hurts nobody other than those consenting to the act (aside from adoption) is not a reason as to why it is morally acceptable.
Also bear in mind, that even if there were no health risks associated with it, it is not indicative of whether or not it should be acceptable.
Science cannot dictate morality, or what is right or wrong, it can only tell you what "is", and to a certain degree "why" that is the case.
Once again in regards to marriage and adoption, it is up to you to demonstrate benefits. I have no burden of proof whatsoever. In fact, even if I say nothing, it doesn't mean that either should go ahead.
Don't see this as a copout. Go read the last 50 odd pages of this thread, reasons against both marriage and adoption are both numerous and mostly secular in nature.
And please, enough with the Bible criticism, I looked at the first 3 examples you listed in either this or another thread (could have been the God one) and they were all incorrect in their description of God's character. If you actually want to take the fight to scripture, then fine, but don't do so with knowledge of the Bible that is limited to the hits attained from googleing "bible contradictions".
Moral relativism is inherintly flawed, and so, what is trully moral or immoral as the case may be, cannot be determined without an appeal to scripture.