If the refs are simply letting extracurricular stuff go, and obstruction type stuff gets called, I would understand. But it's not consistent. In fact I'd argue that most of the non-calls on Nashville I've gotten annoyed over were probably obstruction type plays.
Staal was in the same spot Duchesne was with the puck on his stick. Staal didn't get the call, yet Duchesne did. In both cases, as far as I can tell at least, the referee was in position to see the play. I get that the Staal penalty could simply have been missed via human error but when you start adding it all up big picture and looking at the mismatched penalty totals, the optics are real bad.