When someone pointed out to the homophobe that sex doesn't have an objective purpose, they responded with: "Of course it does, it isn't abstract.
So I pointed out that that's a non-sequitur response and then got this in response:
1) Abstractions don't have purpose, hence saying that sexuality has purpose means that sexuality is unlike an abstract. Simple logic here. 2. Mechanisms always have a purpose, whether negative or otherwise. Also thanks for merely saying no they don't rather than providing an actual refutation. I dare you to name one mechanism that has no purpose other than the alleged intercourse.
"Respect for personal beliefs = "I am going to tell you all what I think of YOU, but don't dare retort and tell what you think of ME because...it's my personal belief". Hmm. A bully's charter and no mistake."