I had a discussion about this between some friends and actual fightan game pros (Mike Ross and Gootecks) so I'm pretty sure this opinion is pretty valid.
These two fighting games have the worst fanbases period, they aren't terrible games but their funs are just the worst. You seriously cannot fathom my distaste for these two fanbases.
The first being Melty Blood, as in the doujin fighter based on Tsukihime the awful visual novel and even worse anime. The games themselves are mediocre but the fans are exactly what you'd expect from a VN fanbase: the worse kind of neckbeard weeaboos. They have major tournaments where they fight for love pillows instead of money and sticks. Yes LOVE PILLOWS, why? Why would someone want to go through the effort just for love pillows instead of the respect first place brings? Expecting an intelligent discussion about the mechanics of Actress Again? Well you'll only find that amongst high class players, everyone else would rather talk about which loli will reign supreme. This isn't a joke this was a large conversation I overheard at EVO 2k10. And the thing that irks me the most about this fanbases is computer matches, this is the ONLY fanbase that would rather spend time betting on computer vs computer matches instead of having casual matches. I was almost turned off from Act Candeza at Evo2k7 because I got in only one casual match before they kicked me off for a computer vs computer tournament.
Now this isn't to say all fans of Melty Blood are this bad, in fact I've met plenty of pleasant ones. But everything I've stated is true for the majority. Just check out this video of the MBAA fanbase, the good and the bad.
The second being a rather big one and loaded with great players but just as many retards: BlazBlue. Seriously for everyone one good BlazBlue player there are at least three other idiots.
Whats wrong with BlazBlue fans? Only one thing and just one thing: They're extremely defensive of the game. I'd say 80% of them are stuck in the 15 year old console wars mindset when it comes to BlazBlue. The majority of the BB fans try and push their game to be better than all others for no other reason. It's in a BlazBlue players nature to shittalk Street Fighter IV, no other fighting game just Street Fighter IV. Which leads me to believe the majority of the idiots in the BB fanbase are just mad that they're terrible at SFIV. For some reason BB fans really hate SFIV, they feel a need to go around hijacking SFIV discussions or make comments that SFIV sucks in arcades or wherever either game is being played. You never see a SFIV or just even an SF player shit talking any other fighting game for no reason. Why? Because SF has done this shit time and time again between KoF, Tekken, Fatal Fury, and even amongst itself between Alpha players, 3rd Strike players, Super Turbo players, etc.
Bring up a problem with the game? They'll chew you out like a giant spoiled Asian baby complaining about getting Dark chocolate Hershey's instead of Almond Hershey's. BlazBlue is full of flaws and most players wont admit to them aside from X character being broken like Nu-13 or Bang. One of BB's major flaws is that AkSys thinks all of its fans are idiots and keeps negating itself by releasing a new version before the previous one has time to evolve. Look at all of the great fighting games of our time: Super Street Fighter II Turbo, 3rd Strike, KoF 2002, MvC2, etc. All of them had time to evolve into a completely new game and let the community turn the game into something else. BlazBlue will never get to experience that because theres a new version every few months. I guarantee you Bang or Ragna wouldn't be as good as they are if Continuum Shift 1.02 had even just a year to evolve.
Tell that to a fan, namely a less understanding one? They'll say whatever bullshit they want but it'll always be translated into "ur stupid and I'm mad."
If you're any type of fan like the ones I listed then fuck you and abandon fighting games, you're doing everyone a favor because no one wants you around.