it's just stupid, and it isn't backed by science. In fact, many videogames actually improve your brain function in many ways. Improved decision making, improved ability to pay attention to multiple things at once, improved vision, improved reaction time... I could keep going. All of this has been proven.

Yes, excessive video game playing is bad for you (excessive meaning spending time playing videogames instead of doiong something that your body needs (eating, sleeping...), but that's not because it's videogames, it's because you aren't doing things that your body needs you to do.

Certain types can be beneficial in many ways, other types should be played sparingly or not played at all.