There's an enormous difference in the government having channels allowing for the disclosing of private material to them and just giving them all of it from the get go, and it is not unlike the difference of allowing the government to jail people and allowing it to arbitrarily jail people for life.

The difference is legislation, in both cases. Permissible data exchange between government services is legislatively encoded. Permissible sentences are legislatively encoded.

Since we don't see a whole lot of moderately healthy democracies arbitrarily jailing people for life, one might reasonably assume these sorts of controls work.