I trust what the players and coaches say on both things. (Kopitar and Bergeron)
I couldn't listen to Faust and Fox anymore the last few years so almost exclusively watched the road broadcast and when they interview the opposing coaches or players, or have an analyst (who was usually a player) they always talk so glowingly about Kopitar, how underrated he is, how he is one of the best two-way players of all-time etc.
But it's basically universally accepted that Bergeron is at another level defensively, and that he probably should have just won the Selke every year from 2005 onwards. I've just heard to many players and coaches say it in interviews how he is at a level by himself, you just have to take these guys for their word. And with the Selke, I'm pretty sure many of the PHWA writers just go off of what they are told in their discussions with coaches, players, managers etc. But I also do appreciate that the player who was probably the 2nd best defensive forward for that entire era was awarded with a couple of Selke's. Bergeron didn't need to win it every year to cement his legacy as the best defensive forward of all-time, but Kopitar having two of them really does help cement his HOF resume.
I think most of the time the PHWA got it right with the Selke, the one I didn't really agree with was Toews winning it. Toews was a good defensive center, but living in Chicago at the time and also following the Kings closely, Kopitar was doing a lot more heavy defensive work than Toews ever did, I think that was another instance where the Toews hype train got a little out of control. Kopitar to me was always a better player (especially defensively) than Toews was.