I disagree... It's not unnatural, lots of species have homosexual members, as for it being illogical, most of what people do is illogical, and not all homosexual relationships are dysfunctional.

I don't think it is an affront at all. On the contrary, I would contend that since we create the definition of our words, and we frequently change them, it would be a small, but natural change to include same-sex unions in the term marriage.