I honestly wonder how legal that is.

If you bought something under the pretense that you could disable cloud stuff and then it silently starts uploading to the cloud, that's a violation of your agreement.

If they start dropping all requests until you assent to their shrinkwrap agreement, that still feels like a violation of the promises they made when you bought it, but unfortunately has precedent. See also: all the video games that no longer work because the publishers stopped supporting the servers they relied on.