I always find its best not to defame someone, no matter how much you might dislike them or their policies, unless you have a specific fact you want to cite?
How about his willful undermining of the integrity of the public comment process for the Net Neutrality regulations for starters?
He got his way aside by refusing to investigate the tens of thousands of fake comments supporting the repeal of Net Neutrality regulations.
Considering that the comments are completely useless for anything except to let the commissioner know what the public opinion is on a topic, it's not like he actually changed any outcomes by not investigating. The comments aren't votes.
Russian election meddling was mainly fake comments/posts on FB, Twitter, etc. Similarly to Pai, the current administration refuses to investigate those fake comments too. Looks like a trend :)