As someone who has dealt with users who use a system in an unintended way, you don't go looking for those people and you don't build something to enforce a policy like this. When you're running services for lots of customers, you often don't know a lot of what's going on in the system and how people are using it. Then something seems weird or something is causing a problem and you want to deal with it - and you want the language out there so that you can deal with it.
In Amazon's case, their bandwidth pricing isn't really defendable. It's just crap. However, sometimes you're trying to offer something reasonable, but need to make sure that a customer doesn't end up abusing something. For example, Chia is a cryptocurrency that will basically wear through SSDs (it's a proof-of-space system). There aren't explicit limits on how frequently you can write to a disk from most hosting providers, but Chia goes beyond what normal usage would do to a disk. Chia farmers would rather burn someone else's SSD that they're renting than their own. But no one at most hosting providers was probably looking at how frequently people were writing before noticing "hey, why are the disks failing faster than we'd expect?"
They probably haven't taken action on it because they probably haven't noticed it being a problem. But if you're a whale of a customer and suddenly your data transfer charges drop off a cliff, someone might end up looking into that and seeing what's going on.
