He is quite obviously acting.
I have defeated your wall of text by removing the center brick.
To be honest, you quite obviously don't watch his videos. Sadly, most people hate him without watching more than 10% of his content for any point of reference. This doesn't just go for him, in fact, but for most anything. He is not acting. Over time, he has accumulated two million subscribers. He would talk during his videos, and as with any YouTube video, people will repeat certain phrases he blurts out in his excitement. He agrees in the humor of this, and of course he repeats it more often. This happens especially with the large viewer base he has.