How would that prevent vandalism? Would it be like a category restricted for trustworthy people? 
Honestly this is very edge case, how often someone wants to reply to a topic but not see bumped, and how often would a bump actually harm the forum’s role as a source of information and discussion? Bumps serve a purpose.
If someone really wants to answer a topic but not bump it, they can still ask a moderator (or admin?) to reset the bump date after they posted.