A meme is a virus; transmitted even unwittingly.
All a virus "knows" how to do is spread, which is amoral.
Whether its spreading is good or bad comes down to the payload.
Does the payload make things better, is it something people would be OK with if given a choice?
In which case it's fine, good even.
If it's something that people would have chosen, after the fact, to not receive, then it's bad.