That's because you haven't thought it through. "We only want info on the bad people" might not alarm you personally until any government entity changes the definition of bad and now you're a "bad guy".
There are all sorts of powers we afford law enforcement that could be abused; I hardly think cameras would be at the top of the list of concerns, honestly. NYC has had thousands upon thousands of cameras for quite a while without much fanfare, along with other major top cities worldwide.
OP knows only a very basic opinion of mine, and they tell me I'm wrong because I haven't thought about it, what else should I think? Do you think they know how much I thought about this?
Isn't the implication "if only you thought more and better about this topic, your opinion would match mine"?