Why are ppl baning Zarya on comp?

I started playing OW when it released, and played for about 2 years i think, or more. I stopped when they release OW 2 i think. I am a sup main, and play tank sometimes. I was a very good zarya (i think), and i know you can do a lot of damage with her. I am in gold now. And almost every match they vote her out. Why?