The ultimate oversight is the voter.
And the voters have decided that the courts should be trusted.
And the voters have decided that the courts should be trusted.
Your argument would hold more weight if the people voting were actually well informed and educated about what the implications of their votes would be. If the government came out and said "everything you do, say, click and load will be saved for latter analysis" do you think they would vote the same way?
(Not that I'd accept building a backdoor just because 50%+1 people wanted access to my users' data, either, but at least then the argument made in the post you replied to would have any meaning at all.)