He's also disliked for being a media darling. He has a close relationship with the press where it's seemed like he's getting protected by them.
You have all sort of mental shenanigans being made out for him to a point where there was a campaign to put him straight back in as a starter when he returned despite being rusty, lacking match fitness and being out for months.
Now, if ter Stegen has cultivated a close relationship with the press and gained their trust or favour then I don't really blame him for it. If you can do that as a player then sure go ahead as long as you're not leaking stuff to them. It's the game I guess. Why wouldn't you do it if you can?
But don't be surprised when fans find it off-putting.