Speaking as someone who is in their 30s, I couldn't care less about the silly voices, the endless repetitive churning out of videos about the same indie games (God knows I'm still watching Bisnap do endless playthroughs of Risk of Rain and Binding of Isaac) or the clearly very young fanbase. Those things don't really bother me.
Now making jokes about rape and the holocaust? PewDiePie can go fuck himself.