We don’t have militarized police because people own guns. I’m sure it’s a factor, but an interesting correlation I ran into recently was that the more African Americans there are in a community corresponds to an equivalent increase in the deployment of SWAT teams. Unfortunately, the available data only exists for Maryland because they’re the only state that keeps track of SWAT team deployments.

https://www.pbs.org/newshour/science/police-militarization-fails-to-protect-officers-and-targets-black-communities-study-finds