The question isn't whether homosexuality is "normal" - it clearly is, for certain individuals. The question is whether homosexual behavior - like heterosexual behavior - is to practiced responsibly and in conformity with good health and social norms. Here, the issue is promiscuity vs. monogamy. I support gay marriage precisely because it presents a vehicle by which homosexuals can practice their sexuality in the traditional, responsible manner - with their monogamous partner with whom they've made a lifetime commitment of mutual care. Without the institution of marriage, it is too easy for folks - whether gay or straight - to act like horndogs without responsibility, leaving victims of their selfish behavior in their wake.
I have known heterosexual couples who were faithful to each other despite having no paperwork involved, never officially married.
I have known officially married couples who were notoriously unfaithful.
If they want to be monogamous, they will be, but
no piece of paper, no decree, is going to impose that fidelity.
Anyone who thinks it will, can add delusion to their insecurity, and I can't think of a more insecure bunch than homosexuals--because most will have sex with just about anyone who strikes their fancy, and some make a point of being predatory and controlling. For a lesbian, "girls night out" takes on a different meaning than it does for the heterosexual, same for 'oh, just over BSing with the guys' for a homo. Everyone is a threat, and no piece of paper will change that. Such relationship difficulties are commonplace for them, and may even contribute to the high suicide rate among homosexuals, who just aren't as 'gay' as they would have you believe. Others are just notoriously promiscuous.
The purpose of imposing "homosexual marriage" on society was to tear at the very fabric of western society, to further destroy the concept of the traditional family, to wage war on the idea from Genesis 2:23-24 that
23 And Adam said, This is now bone of my bones, and flesh of my flesh: she shall be called Woman, because she was taken out of Man.
24 Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.
Traditional One man/One woman marriage is the foundation of the family and society, and has been for thousands of years.
Homosexuality produces no progeny, the family is not essential to the relationship, not even for the purpose of establishing estates and trusts and leaving those to whomever they please--which they can do anyway. Medical power of attorney on file would give their partner the same rights as a spouse. The means existed to do legally what they would without trying to shred the fabric of the society which tolerates them.
It's just a thumb in the eye of the 'breeders', and a sneer at The Almighty, himself.