The show is actually fairly popular amongst the male internet nerd demographic. The original creator, Lauren Faust, was a well-liked animator beforehand, and something about it just caught the popular imagination ('nerdy' references, characters and animation, well-timed slanderous editorials, etc.). There's a huge fandom that constantly produces ludicrous streams of stuff.

There's been some discussion of it on LW, and I expect there's a not-insignificant population of fans here. Or "bronies", as some style themselves.