Game Grumps is interesting in that, over it's run Arin, Jon and Danny have broached practically every issue, discussed every topic, and most likely crossed some line for each viewer. Yes, I'm saying that some people could find certain things the grumps say offensive, or become enraged by how they react to their haters (hating the response to hatred is very meta).
Of course, there are still fanboys who will defend anything the Grumps have ever done. However even they will probably find the Grumps did something annoying at some point. For many, it was replacing Jon with Danny. Game Grumps is a very real show and it's really all about the friendship, particularly in less gameplay-focused playthroughs. Arin and Jon have (had??) a truly once-in-a-lifetime friendship, whilst Arin and Dan's seems more run-of-the-mill (partially because they're so very similar personality-wise).
It is because of this very realness and the emphasis on friendship, however, that I can forgive anything the Grumps ever do: we are being offered a window into their lives, not in an incredibly specific or private way, but so that we get the very sense and essence of their relationships. This truly is how they act, and so some find it hard to separate it from content that can be expected to be thought out beforehand: this is not a movie, nor a JonTron episode or Egoraptor cartoon, where you can say "what were they thinking???" because if you recorded everything you said with your for 20 minutes, you would not want that on the Internet. But the Game Grumps are brave enough to put it there for the entertainment of others, and for that I