When something becomes a trend, people flock in to it. They also want to be cool.
I get it, not everyone likes the same kind of music but I'm not spending my time making memes about music I don't like. If that would happen, it might be time to evaluate should I really be spending time doing this? It takes time to realize there isn't bad or good music, they are all just catering to different tastes, made by people with different taste.
Personally, I like several songs from Nickelback!
It would actually make more sense to me if Nickelback faded into obscurity while these people raved about acts they actually like. But if there really is "no such thing as bad publicity " maybe this is working for them on some level...