Also there isn't a rule against bumping shitpost so when you see one use the report to moderator button and wait for moderators to make the judging decision.
I mean shitposters have rights to bump their shit posts. If they got reports, they will get reports on their original shitposts - as spam, not bumping posts (if they don't bump their shitposts more than once per 24 hours).
Bumping makes more sense if authors bump their good posts (for visibility), because without bumps, their good posts will be burried under other shitposts and shit bumps.