Many people have different theories, they promote violence, make you want to harm others. Bit to me...they don't, like I play the Call Of Duty games and I don't experience any of these thing. To me they don't "Rot my brain."
Only thing that can rot your brain is a disease. "People" think that if you send too much time playing video games or watching tv you don't stimulate your brain enough to become more intelligent. An example of not enough intelligence is writing long sentences without punctuation marks.