If you make money through ads, you either use one of the few companies that accept porn

I don’t get this one. Why won’t people advertise on porn sites? A people who watch porn less likely to be customers? Or are they just as good, and there’s a huge market untapped outside of gambling and porn and everyone should advertise their services on porn sites? Or is it that the only companies that are good at figuring out what specific ads to show just refuse, and in an alternate reality where they didn’t you could just as easily advertise on NSFW websites?