There’s certainly an argument to be made for Tyrande’s stance, and as we already know from SL she seems more focused on Sylvanas than the Horde anyway. The point was that from a player character perspective you can latch onto the “no peace, only vengeance” or the “only good Horde is a dead Horde” mentality (even if you don’t care that much about what happened to the elves in particular). You can call it righteous anger, but those are not the stances of the “good guys”.
Even in the real world when terrible war crimes have been perpetrated we don’t wipe whole nations off the face of the earth in retribution because it’s understood that you don’t hold everyone responsible for the actions of a few.
It’s unfortunate that the game doesn’t really let you play out any sort of political subtlety. If you’re part of the Horde then you side with the evil raid boss until they become a raid boss. Often times the world doesn’t even reflect what’s going on with the story either.