Just playing devil's advocate - but this is democratically consented to.
Your elected politicians have specifically allowed the sale or transfer of retired military equipment to state and local police forces, for multiple reasons but the least-of-which was cost savings vs. scrapping all the prepaid equipment.
Similar, but admittedly not quite the same, to the sale of demilitarized Humvees, tanks and fighter jets to civilians. Or NASA owning and operating former US Navy F/A-18's, B-52's and more... war machines now repurposed for peaceful training and aeronautical research.
Just as a random question, how many people do you think know that these guys (https://longreads.com/2019/06/21/nothing-kept-me-up-at-night...) are flying above American cities
I have a suspicion, being a Senator for 40 years sort of removes you from the concerns of everyday Americans.
These are the same Senators (and Representatives) that vote for these measures. They'll never be the target of these surveillance schemes... and when they are, they throw a huge fit[1] because they're supposedly above all of it. They're the same people who ban guns from the public, but own operate and illegally traffic them themselves[2].
They're the same ones that don't have to be strip searched every time they fly, but I digress...
[1] https://politicalticker.blogs.cnn.com/2014/03/13/pelosi-alle...
[2] https://www.washingtonpost.com/news/morning-mix/wp/2016/02/2...