PrincessLucina said:
It seems like an odd question, but, in all honesty seeing as how some fandoms seem to be going lately, it's a genuine one. Are massive groups of people all loving the same thing really a bad thing? The reason I ask is that I was talking to my girlfriend (Who I tried to convince to get into Steven Universe, only for SJWs to scare her away. I did succeed with Undertale though, to an extent.) and she said that no matter what piece of media you try to get into, whenever you're new you're always ridiculed, looked down on, and mocked for not understanding the media you're really just starting to get into. I for one can attest. I tried to get into MLP and Fnaf, much to the same result of 'If you don't know it when you join, we're ignoring you.' In fact, pretty much all the fandoms I've tried to join (Aside from Undertale and Dr. Who) Have this same effect. So, are Massive Fandoms a BAD thing?
I'd say it depends on the people who make up a particular fandom and what generation/age groups comprise it. Star Wars and Star Trek have massive fanbases, yet I've only encountered what you're describing in a few cases with them. Most Star Wars/Star Trek fans are supportive of new people joining, though they'll want you to get more involved than just watching a few movies or T.V. shows. These two fan bases also have fans who span generations (same thing is happening with Transformers, Teenage Mutant Ninja Turtles, and Power Rangers, as more Gen Xers and Millennials have kids), so you'll see fans trying to get their kids to enjoy the newest iterations of these series, or share their fandom with younger/older audiences.
As with almost everything in life, things are defined by the people who operate/are a part of something. It'd be more accurate to say that the Steven Universe fan base has people who are assholes, rather than attribute those jerk fans to the fan base itself.
In a nutshell, I think having a massive fan base is a good thing for the series, and for those wanting to join such a community. You just need to navigate through the jerks to find a particular group you're more comfortable with, or one that's a lot more accommodating.