Not need to know
It's one thing to be unaware of traffic content in general and completely another to deliberately look the other way while encouraging illegal and unacceptable traffic for gain.
Web traffic to the servers of the notorious Dutch-German Cyberbunker hosting biz was filled with all kinds of badness, including apparent botnet command-and-control and denial-of-service traffic, says SANS Institute. Cyberbunker, aka CB3ROB, was raided last September by 600 German police gunmen who forced entry to the outfit's …
German laws are different. From the Reg article about the raid in September 2019:
"German law says ISPs cannot be held liable for the activities of their customers unless, roughly speaking, they actively collude in it."
I'm assuming that knowing illegal activity is going on, and then continuing to provide services that facilitate that activity, will be enough to break whatever the German laws is.
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