A lot of statements and theories about these camera's from all sorts of directions, but they're just pole cams. LEA's have been using pole cams since before I was born (I'm 34). I worked in law enforcement as an analyst and spent some time staring at pole cams that were setup to surveil known drug dealers or criminal gang members. To do one correctly (i.e. legally) you typically need a warrant or a court order, but it can vary I guess based on jurisdiction. They're often deployed as an alternative to human surveillance efforts. They're called pole cams because, well, they get thrown up on telephone poles usually, to take advantage of the power source and ease of view. The surprising part of this isn't the cameras, its the fact that these are wide open on the internet. But honestly police are not IT people, and they often have officers or agents that work specifically as "surveillance techs" who are not IT people either.
I imagine this will draw a ton of ire about privacy and such, and I generally agree, but from my limited experience with them, they aren't wide spread, they're typically temporary, and they're usually purged except for the parts that are relevant to the investigation. These cams appear to be the exception, not the norm. If I saw a cam was sitting on an openly accessible server like this I would have filed a complaint with the agency and the OAG. I don't live in a state where any of the ones listed on Reddit are in, but I would encourage people who do live in a state with one of these cams to notify your OAG about it.