I have read through the rules I agreed to during registration, and found nothing of this sort. Please show me the part that says so.
The repositories I installed all contain addons with legal content that I intend to use. And I do not use any of them for illegal purposes.
Saying that a repo itself is "banned" or alike, because it is possible to use it for video piracy, would mean that LibreElec itself would have to be treated the same way. It is possible to use any device for illegal stuff, but I don't do this, so I do not see the point in removing anything (unless you can actually show me the forum rule that states otherwise).
you are fighting a losing battle, either get rid of them, or get no more help. The choice is yours