Your understanding is a bit oversimplified. What the members of WSB are trying to execute is a forced short squeeze to take advantage of naked short positions, which are themselves of questionable morality. However, this is not market manipulation, nor is it a pump and dump. If you read the rhetoric carefully, they are "holding because they like the stock." If this qualifies as market manipulation, the argument is that virtually any strategy employed by any hedge fund or investment firm anywhere would classify as "market manipulation," probably to an even greater degree.