Some silly person went to all the trouble to register a few hundred new accounts and give them all user profile pages full of spam. Because I don't have time to deal with this BS, I have simply disabled user profile pages for all user IDs above 500. That should keep most of the original users' profiles visible while blocking most of the spam. New users will not be able to create profile pages/bios/etc. Of course, there hasn't been a genuine new user in years so I doubt anyone cares.
Sorry for any inconvenience.