Personally, I think a lot of the "Subban has an attitude problem" is a subtle racial dig. We've heard the lamenting for a long time over the fact that too many pro players act like robots, then when someone comes along that challenges that at all, he's cut down pretty quickly.
The common theme among the ones with "an attitude problem" I can think of is that they're not English-Canadian. Mario Lemieux was French-Canadian. Brett Hull had dual citizenship and represented the USA internationally, and both he and Lemieux took a lot of crap for being perceived as "whiners" (a label never assigned to Steve Yzerman, who plenty of actual officials said was the biggest whiner in the game). Alexander Ovechkin is Russian. PK Subban is black. Basically, if you're a white Canadian who played in the WHL or the OHL, you're fine...anyone else may be tagged as "head case" or "attitude problem" or "locker room cancer".
From my own observation, a lot of the average white guys that are considered cancers have names that end in -ov or -ev. Hell, the biggest issue/non-issue this year was how an 18-year-old Nail Yakupov celebrates scoring a goal. There are nonstop questions over seemingly everything about Alexander Semin. No, it's not a strictly racial thing, it's a "different" thing led by the hockey media. It's the difference between "eccentric" and "flaky", between "inconsistent" and "enigmatic", between "quiet" and "unemotional".
I'm simply saying that over the years, I've noticed that there's a clustering of the more negative toward players who don't fit a particular profile. I've noticed it in researching both baseball history and hockey history.
I find your rationale pretty weak. Yzerman never took the flak Lemieux and Ovechkin have, so there must be an English-Canadian bias in the media? Give me a break.
That must be why the media is so hard on Datsyuk and Malkin but take it so easy on those good English Canadian boys Sean Avery, Matt Cooke and Dany Heatley (yes I know Heatley was technically born in Germany but he was raised an Albertan), among many many others.
Hockey players have a tradition of being less flamboyant than many other professional team athletes. Part of it probably comes with being in a sport where there is a long history of players policing themselves - do something that embarrasses the other team and your apt to get a fist in the mouth or a stick across the back of the legs.
Players that have flashier personalities are going rub some of the more traditionalists (players, fans and media) the wrong way. Some players are just awkward in their social interactions, and so they get mis-interpreted as being aloof a**holes. Finally, some players actually are a**holes (I'd like to think English Canadian Jeff Carter fits here).
Don Cherry aside, I don't see a racial or nationalistic bias by the media being a prevalent issue.
As for Subban, I have no idea what he is like off the ice. But I'd love to have his skills on my team and I don't see why Montreal would trade him right now.