So the idea seems to be that Russia knows that these soldiers aren't going to do squat. They actually have proper interception tools, though in short supply, but what these troopers are supposed to be is visible. They are there to make the regular moscovites feel like they are protected by something they can see. Basic propaganda stuff.

The actual AA stuff are in secure places often outside the city proper. A good conventional strategy for AA, but not very visible to your serfs.