@Alpha
I highly doubt that's the case. I don't think they're jealous of how many Smash tournaments there are.
As someone who went from Smash to Street Fighter and BlazBlue, I'll toss in my guesses. (not necessarily my views)
1. The roster is freakishly unbalanced.
I shouldn't have to go into this all that much. The quality differences between Meta Knight and Ganondorf should be enough evidence.
2. The series is made by anti-competitive man.
Read up the interviews with Sakurai. He's like that because he wants it to be super easy for beginners. That's fine in itself, a good thing actually, but the lack of stuff you can do in these games outside of physics exploit and some glitches is rather limiting which brings me to the next one. Not to mention that this is what prevented from us having leaderboards.
3. The movesets are totally minimalist.
Look at how other fighting games handle movesets. For example, in Street Fighter, there is a template for normal moves that everyone shares. Then you have your unique normals (ie overhead) and your specials. Someone like Cammy has no "unique attacks" and has about technically five specials. Guile has more "unique attacks" and only two specials. Super Smash Bros. forces every character to have no different kinds of A attacks outside of the template and every character must have four and only four specials. For characters like Link and Samus, this is very limiting considering the number of tools they have in their games. On the other hand, the Ice Climbers had to have stuff made up for them.
The motions in other fighters remove this constraint. The directions in Smash keep them, in. For those you wondering, tradtional motions aren't to hard. The hardest you might have to deal with is the 360 motion and maybe the charge motions (at first). QCF and such are all rather easy, IMO.
For normal attacks, you have A and only A. Most fighters have at least three different types of attack buttons and they're usually Weak, Medium, Strong you may have more in others (like six in SF, 4 in BB). Smash keeps it at just one which is a mixed blessing. Heavy characters can't really have quick weak attacks, and the opposite applies (within balance) as well.
4. The alternate playstyle.
I don't think this is as strong as the others, but this is what turns some people off. Nonetheless, Smash brought about a new genre of fighting games. I suppose though, if you wanted to satisfy traditionalists, you could go the Soul Caliber route which does traditional K.O.s and Ring-Outs, but then comes the question of whether or not the settings reset each round or not.
EDIT: Just to clarify, I'm not against the playstyle actually. I think it's a nice take on the genre.
5. The tournament attitude
I've never really heard a lot of good things regarding the Smash community. I've heard it being called immature and ban happy. One thing I don't care for is that I always hear about money being involved.
To be honest, I think there's a lot that can be done in SSB4 to fix a lot of the flaws up without losing its platform fighter aspect and DI.