There's a difference between O'Reilly and everyone else in that he has twice held out for more money, saying he's worth more than he's being offered and now he has come out with 3 completely lackluster games in a row.
He's being "mocked" (mostly in jest by most people, except those that don't like him at all anymore), because someone that's just been given a big pay day and talked themselves up as being this amazing player is now seemingly giving less effort than he ever has in his career.
Whether it's nice or not, O'Reilly doesn't get the same pass as everyone else does (And believe me, McLeod and company haven't even been given a pass) because of his salary demands. If you're going to demand to be paid the same as Duchene, you better damn well perform like Duchene.
I'm sure Ryan will turn things around, as the team will, and this will all be forgotten, but there are damn good reasons why he's getting **** on more than anyone else.