This is the sentence, in Hetzners ToS, that you're referring to:
"In the case of non-compliance, we are entitled to lock your access to the Service and/or to your account." Source:
https://www.hetzner.com/de/legal/terms-and-conditions/#16If your lawyers thought that this line means something different than "don't use crypto, mining, etc. we will lock you out", you should change/sue your lawyers. This is a clear as it gets, I see zero fault on Hetzners side.