Why is Mei so hated?

Mei was hated because she used to be just w + m1 then m2 a few times, like pyro but way less fun

I don't think she in overpowered. If you know how to play any characters well, you can be annoying to your enemy team. And if you know how to counter Mei, then she is not annoying. But of course good Mei is annoying, she is like mosquito flying around you Haha.

that great on high ranks and super power on low ranks .

because nobody likes getting frozen for 2s and not being able to do anything while you watch mei press m2 in front of u