Like everything in life criticizing something or someone is easy, it's doing better that's the hard.
I'd love to see/hear some people who are overly vocal against caster A or B cast a game, even if it's just for them to understand how shit they really are and how hard it really is, maybe then the caster position and job will start getting some of the recognition it rightfully deserves.
As for the sellout claims, don't forget that most, or even all, of them started doing this in their spare time as a passion thing or a joke. As time passed and the game and community grew, casting became a full time job and not an hobby. Aren't people supposed to get payed for their work? How do TV and radio networks work? The commercials are a necessary evil to sustain the public demands and the caster/stream channel needs.
tl,dr: stop the caster bashing please.