Where does the anti-MMA sentiment comes from among BJJ practitioners?

I've seen it a lot online and expierienced it myself, but it seems like plenty of BJJ practitioners have some sort of disdain towards MMA practitioners/fighters or to mixed martial arts in general. From laughting at grappling skills of UFC champions and saying how they'd fold them, to just saying that their art is the best and MMA sucks, what do you think is the source of it? Maybe it's just me, but I think plenty more people have encountered it. And of course there are lots of great folks who train BJJ and I've met plenty, but I just mean the general sentiment.