Sounds like a completely legitimate use though. Hetzner were widely telling people about that 20TB limit, so why would they be surprised when people use them as CDN boxes?
I prefer to assume naivety over malice/negligence.
Like, this is not Netflix tripling the prices over a few years.
The engineers said 20TB in aggregate was fine but likely didn’t consider the “bad apples”. Marketing obviously wants to use the biggest numbers and then finance comes in with the hammer and dev points to egress as an simple way to upset rhe fewest number of real customers.