If you don't understand why intentionally trying to injure players (who aren't even involved in the play anymore) is a lot worse than bagging an interview, I doubt anyone can explain it to you.
Wait, where did I say they were even the same? Of course, hurting a player isn't the same as refusing to talk, but my point was that both constitute not doing your job, either by not playing between the whistles or refusing to answer questions...and both are rightly fineable offenses.
In fact, I'd argue that Lynch's fines are completely avoidable because he's more calm, likely has already showered and is emotionally removed from the game so he has no excuse.
With Suh's ignorance, I can at least defend the fact that he's emotionally wrapped up in the moment and it can be much harder to keep control of yourself.