Over the course of the last 20 years, we've seen that once a data collection and digital surveillance framework is put in place, the surveillance tends to expand.

Slippery slope arguments, sans good reasoning, tend to be fallacies. However, don't fall into the trap of thinking that an argument backed by historical record is a slippery slope just because it's predicting an outcome. We might call that the "history is all slippery slopes" fallacy. Stating "this has happened before multiple times before, and each time has lead to x" is a very different argument to stating "this has happened, so the logical extrapolation is x".