Keep in mind that I'm not entirely sure what has happened, but from information that I have gathered, here is what I have pieced together.
Purple Tinker was, and stil is in a way, an influential member of the fandom. She was a former organiser of Bronycon, the largest and most popular brony convention. She had stepped down, over reasons that I'm not aware of. However, I have heard that it involved some drama between staff members.
Now here is where it is a bit hazy. Rumours were spreading about Purple Tinker that weren't the nicest of things (such as stealing money etc) and Purple Tinker was able to prove these rumours wrong via her DeviantArt account (link:
).
So, a ton of other brony conventions start opening up, which is fine, but apparently, Purple Tinker tried to get people to shut down the cons, such as fellow bronies, and even Hasbro. However, her attempts were fruitless, as Everfree and Canterlot Gardens have gone on just fine.
However, from what I've heard, Purple Tinker started spreading slander about the cons, saying things about how there were rape jokes made during the CMC panel, and that there was racial slurs in the hallways at Everfree, and all that nasty stuff. The supposed reason is because the organisers were former Bronycon staff members, who had had fights with Purple Tinker in the past.
That is why people dislike her, because she was spreading false rumours about the cons.
Remember, I'm not sure how much of it is true, because this is all information I have gathered that may or may not be biased to either party, but in my opinion, Purple Tinker shouldn't be spreading slander about the cons, even if she doesn't like the people who run the cons. She had lies spread around her, so she should know what it feels like, shouldn't she? If this is true, then that makes her in the wrong, because she had a responsibility, and a lot of people were on her side, but she threw it all away for her own gain.
I'm not sure if the situation has developed anymore, but like I have said, this is based of evidence gathered from her DeviantArt page, as well as Twitter feeds, Tumblr posts, forums and news sites. If I have anything wrong, or there is more evidence, please don't hesitate to tell me.