I keep seeing this one artist's listings for gross sh*tacon content in the Comics and Everything Else categories.  I'm positive I've blocked them, but I can still see their works in those categories.  I've reported stuff like this before, but the individual users and projects still seemed to stick around.  Is there any way to fully report creators?  I don't want to see that kind of thing on this platform ever again.

Assuming you mean fully mute them, no. Blocking should help. If it doesn't, that might be a bug or omission. Try contacting support the normal way, reporting is for projects that shouldn't be on itch.io at all.

If you rate the projects with a 1 the platform should figure out that you do not wish to see that kind of projects. Also do rate projects you like so itch can show you more of it.