I don't see a lot of, "Rebuilt identities" around the show. I see people who genuinely enjoy the show, and also appreciate the irony behind a My Little Pony show being so bloody enjoyable. That irony is funnier the more prevalent it is. Don't mistake a joke for serious obsessiveness, and remember that just because a lot of people like MLP doesn't mean they don't also see how ludicrous that fact is.
Also, the MLP Meme (And I mean this in the more scientific, unit of culture sense, not the strictly internet phenomena sense) propagates so well because it is a great subject. Go find a random, silly MLP video on Youtube. Chances are, it will be well edited, high quality video, lip synced and polished. Pictures will be appropriate, with some time put in, and generally be pretty high quality. And lastly, cartoons, especially children's cartoons, do a absolutely wonderful job of presenting a very strong, simple, iconic image. If you want to get across the humor behind something being crazy or ludictrous, there are plenty of options. Maybe a scene from Monty Python, Charlie Sheen, or some other icon. But they all require some prior knowledge, a certain consideration for the current state of pop culture, some context, and that can relegate the meme to a niche. A picture of Pinkie Pie hopping while wearing fake glasses immediately communicates that idea to anyone, anywhere. If you need to communicate a passive, shy individual acting unusually aggressive, that idea will be instantly communicated through a picture of Fluttershy yelling at that dragon. Cartoons simplify things so they can be understood and identified with more broadly, both through the act of drawing itself and the storytelling technique, and MLP manages to do this spectacularly well. MLP is so meme-tastic because it communicates so much so simply. Go look at a picture of the cast. Pretend you have never seen an episode. Odds are, you already know a huge about the characters just from there pictures.
