Why do preachers even bother preaching at gay pride?

So today me and a friend went to gay pride.

Of course by the park entrance, some whack job preacher saying how we are going to hell if we don't repent our sinful ways.
At one pint he said, "What you are really celebrating is when a man puts his penis into another man's anus". I was like "Well god damn, he had to give the medical explanation when he could have just called it "poking the brown eye". The fuck do I know...

Of course parade goers just mock and laugh about it, I mean these weird preachers. Lesbians or gay men kissing, laughing, flipping the bird, whatever.

Why do the preachers bother? I don't think anyone at the parade minds, it is comic value really. But for real, who would want to stand there and make a complete ass of himself in front of 1,000's of passerby's? This fucker has nerve.

I also wonder if they would do the same thing at a motorcycle rally?