"Not only that, but if I make money selling porn, do you want me to use my power accrued from people's lust to be used to promote some agenda completely unrelated like say... teaching creationism? People need porn, but most people don't want creationism. So should porno buyers be forced to indirectly support creationism?"
Even if you're just a clerk in a porn store or a model on a porn site, customers are equally "forced" to support whatever you do with your paycheck.
When I give money to a company, I am in no way "forced" to support anything the company or any employee does afterward. I've spent my money; it's theirs, now, not mine.
If I really don't like what they do, I can avoid buying from them.