You don’t need user consent to retain data that’s arguably needed to provide the service itself. I guess, safety falls into that category. Training on that data is probably a grey area, if they can guarantee it won’t contain PII. They have stolen all the internet, so I wouldn’t bet highly on their restraint.
It's very easy to prove that training is not necessary to provide the service, because whenever you're using a model it's static and the training only maybe goes into new models.
It doesn't say for whose safety. It's certainly not yours.