My best guess is that pornography cemented itself as a pillar of Internet culture from the moment it became popular (yada yada, Rule 34, you've all heard this spiel before). Suddenly people were able to just look up porn and download it instantly instead of having to scour for highly specific magazines or tapes. It was an unregulated "wild west" market where parent groups and moral guardians barely had any say, if at all. Because of that, "The Internet is for porn" or "The Internet is for porn and cats" became not just a meme, but a cemented fact for the most loyal of Internet users. And thus, porn artists like Zone, Spazkid, and Shadman were hailed as titans of their craft.
A lot of the content we consume today was built on the backs of porn, as porn is how a lot of people today even got jobs in the industry to begin with. Such as how Zone got hired to work on Skullgirls as an animator, or how Rebecca Sugar got hired after she gained notoriety for...
"you know what." Any time this morality is questioned, people appear and stand their ground with such deflections as "It's about free speech and a free Internet" or "It's about helping 'the little guy'" or, as stated before, "The Internet is for porn."
And they're always willing to show their undying loyalty, now matter how obscene the very thing they're defending actually is. Because, at the end of the day, "sex sells."