> If the police stationed officers constantly at major intersections doing that, the outcry would be no less than having cameras do it.

No.

A police officer is an expensive asset that requires a lot of investment of both time and money to create. [0] When a police department chooses to put cops on a corner doing surveillance, they're choosing to prefer that activity to any other thing that that cop could be doing. In all but the smallest towns out there, it's certain that the PD doesn't have enough officers on staff to surveil every single street corner in town. In most towns, it's prohibitively expensive (in terms of training cost, opportunity cost, and salaries) to set up a dragnet surveillance when one only uses humans to do the surveillance.

In contrast, cameras are far cheaper to acquire, deploy, and maintain than cops. You also only need a handful of cops to run such a surveillance system, rather than one on every corner. With cameras owned by the police or town, it's totally feasible to set up a dragnet surveillance system in most towns.

As many folks have said in the discussion about this, scale and expense are very important considerations. As few people have said, laws, regulations, and punishments that make sense when you will catch one rulebreaker in a hundred thousand often do not make sense when you will catch one rulebreaker in two. And the sorts of regulations that provide adequate restraint to police and prosecutors from interfering in people peaceably going about their lives are not the same in a society where one has to send out police to ask people face-to-face for information about someone's whereabouts as they are when police can sit at their desk in HQ and pull up complete records of 90% of that person's daily activity with five minutes of keyboard work. [1]

[0] I make no comment as to the average quality of the asset produced. I only note that it's a very limited asset that's expensive to produce.

[1] Note that I'm not saying that the surveillance systems currently deployed provide access to 90% of everyone's daily activities. This is an illustrative example. However, it takes only a few minutes' thought to notice that the police's powers of surveillance are far greater today than they were in the late 1700s.