This isn't about technological autonomy. OP signed up for wireless service that is specifically sold as Hotspot WiFi-first. That's one of its main features. It's sold as that very, very clearly. If you don't want their WiFi, go get service from another provider!
Just because a service is marketed as having a feature doesn't mean they have an excuse to undo a user setting in their OS that explicitly says they don't want to use it. Maybe they do want to connect to the advertised network when traveling but auto connect shouldn't be forced on them.
I don't understand why you are trying to defend this so adamantly.
