If they had to find content related to a specific post, they might as well write content themselves. This is the point. This kind of rule would also make threads more interesting and less hard to read because there would be fewer posts that add zero to the conversation.
Once they are banned, any signature they had is removed. I can only speculate as to what he is doing. Some of these people might be participating in FaceBook, Instagram and whatnot advertising campaigns, while hoping to rank up with plagiarized posts in order to eventually participate in a signature campaign or otherwise earn additional money with the higher rank.