I'm not questioning the real-world implications and challenges real DID sufferers face, and know that not all of the alters they get are rays of sunshine or even remotely pleasant. I've met quite a few of them in my travels.Short answer: attention.
Long answer: it's not too uncommon for DID sufferers to get unfavorable alters, such as one who is very angry and lashes out at people when something happens to trigger it. Tumblr fakers like to exaggerate unsavory headmates inside of them because it's a testament to how "mentally ill" they are and they'll get pity points and/or Tumblr dollars.
I was more taken aback by a Tumblrite claiming Chris-chan as an alter, unfavorable or no. These Tumblr kids are picking and choosing their alters (whereas the legitimate real-world DID cases don't get to choose to be the cute little anime demiboy magical girl bunself). Attention aside, I'm legitimately bewildered by the deliberate choice of Chris-chan. It's just, I can't wrap my head around that.