The only "marketing" a mastodon server does is the description on the main website though, what matters is who joins the server. It seems that people who would join a server that was characterized in the press as "free speech above all else" love racism and porn. It's the people on the server, not whatever the administrator claims to want.

I'm on mastodon.scholar and the most risque thing anyone has posted was a closeup of Neptune's uncensored moons. I don't disbelieve you, mastodon is part of Earth and unfortunately that means there are racists there, but I don't think your experience is typical.