Why are there some very overly sensitive people on the Internet?

[Maddie]

I noticed in forums the majority of them seem to suffer from some mental illness, namely a personality disorder..

I made a comment about Demi lovato, she posted a twitter picture of her "natural makeup" I commented on her pose, and that I would find her to be a decent person if she got the help she needed and stopped pretending to be someone she is not and lying to her naive young fans. Within 5 minutes I got 30 messages in my inbox, people or "stans" (stalker obsessed fans, see stan by enimen video for reference) jumped on me saying I'm a horrible person for making fun of her eating disorder and that me saying, "I dont really know why some girls pose like that, jutting collar bone out like that on purpose.. why do they do it?" meant that I am making fun of her eating disorder, what a terrible disgusting person I am, and they usually included their own irrelevant personal issue/experience with an eating disorder. My assumption is that they are overly sensitive.. assuming that I'm making fun of a serious issue when I was doing no such thing.

I've had over 100 comments by 5 different people with similar "Stan"/eating disorder/overly sensitive backgrounds. I've also seen these same people jump on anyone's throat if they say anything remotely opposing any celeb they obsess over.

Did I say something wrong.. or are these people just not well in the head..?