Back in '09 when both groups debuted, there was a certain amount of rivalry and "friendly" competition between the two. Fast forward 2 years to the present, and it's obvious who hit the jackpot: B2ST. Through a constant stream of similar-sounding, but admittedly catchy hit songs, they have become (what Charles would call) a "top tier group", with a larger Daum cafe than mother-fucking-SHINee (who admittedly have 0 public awareness in Korea). On the other hand, MBLAQ has a solid fanbase, sure, but in the grander scheme of things, they're just 'those dudes' that linger in the background. Even rookie groups such as Block B are already making more noise.
Fangirls are raging about B2ST being out of line, rude, and disrespectful. I find that they were simply being brutally honest (think: Key). No doubt both groups are aware of + acknowledge the fact that B2ST is more popular; it isn't some fucking secret. I suppose this is a more legit issue to get frustrated over (as opposed to some of the ridiculous shit fangirls fight over), but the fact remains, y'all need to get that fuzzy shit out of your asses and relax.