She's pretty much the best so everyone uses her. That also kind of forces anyone who wouldn't have used her to do so anyway, or else they'll be at a serious disadvantage. Then there's no obvious "second favorite" as far as I can tell, so banning her would increase the variety significantly (as opposed to everyone just opting for the next best character). That's why I'm leaning in favor of it, anyway.
Also yeah, going to #pofvgrillz and just asking for help would be the easiest way to have netplay explained to you, and to just play casual matches, etc. Especially if you're new to it, you should try to play a lot before the tourney, since the latency takes some getting used to.