Your post is chocked full of logical fallacies: the assumption that only people who think, or live, like you are moral; people who think differently from you are morally corrupt and twisted; the use of the “straw man” and “slippery slope” fallacies by saying that legalization of gay marriage will herald pro-beastiality legislation. The fact is that people have been suing for the legalization of beastiality for decades.
The legal suit you sited is merely an example of Observational Selection Bias. That is the effect of suddenly heeding things we hadn’t been cognizant of before — but we wrongly assume that the frequency has increased — like when we buy a certain model of vehicle and suddenly we start seeing that same vehicle all over the place. Since that suit was brought so soon after SCOTUS’s ruling that denying marriage to gay men and lesbians was unconstitutional, it reinforced in your mind what this senator had said. This doesn’t mean that there is any relationship between the two things except in your mind.