I often get 4-5mil PP in Union events without even really trying. If I used all my BP on CD, I could easily multiply that. Also, simple bot scripts are not something that Nutaku seems to care about. They're not doing anything that a human player (or several taking shifts) couldn't do.
Shia-chan was altering data in memory to access content that wasn't normally available (Ultimates before they existed in our version) and to duplicate items. Not only did he do this, but he bragged openly about it in a highly obnoxious manner just to troll other users. He was absolutely deserving of a ban, if for no other reason than to preserve morale. Users like that subvert the entire community.