They were requesting it from Amazon, not from the neighbor. And it absolutely is wrong (weird is not a word I would use to describe police using their power unscrupulously) to take data that you know is irrelevant.
You did not specify any of this information in your comment. You just said that without Amazon's knowledge the police wouldn't have known that the cameras were there.
Well in fact yes they could have. By just asking the neighbors. And then summarily submitting a request to Amazon to get all relevant video all in one go.
We don't know all the details of the stories you refer to, so you have to provide all relevant information. For all we still know, you are just making assumptions.
I would say it would be standard practice to go check all neighbors with sightline for any kind of recording. Local or cloud based.
No assistance from anyone needed to go ask.