I don't know how you cannot consider him a bad coach.
He has no control over his lockerroom. In fact, he CREATED the lockerroom problems by standing in front of a microphone and ignoring every precedent the rest of the NFL HCs have set about the value of being professional, non-braggard, mature people who do not create much less overreact to up and downs. When the HC cannot find a camera that we will not brag to and overrate himself and his team, how can you not expect the overwhelming selfish, lack of team concept attitude that has infested his lockerroom?
On top of this, he has stuck behind a QB that is terrible. If he doesn't have the sack as a coach to make a QB decision and lets the GM force him to play his draft pick and hope he stops sucking, then he is a terrible coach. However, he has had absolutely no trouble getting criticism of the front office into the media as well as criticizing their draft picks, so Rex Ryan wants Mark Sanchez as his QB and that means he is a poor coach.
He supported Schotty until the players complained too much, then dropped him. He allowed a dysfuntional WR who is lazy, selfish and not close to team oriented decide on who would coach WRs.
He took over a decent team that got handed an underserved gift trip to the playoff his first year, and has legitimately reached the playoffs 1 time in 4 years. His team has consistently deteriorated to now being one of the worst in the NFL. There are only 6 NFL teams with worse records today.
If that description isnt a bad coach, what are you looking for?