A peaceful person filming police is a big part of holding our government officials accountable. It's true that we shouldn't just assume any violence on one side is/isn't justified and justice should always be the focus but we need more than just expecting police to hold their own accountable.

By your own admission you've only encountered the police a few times and probably at most in a few places but probably in the same city/region. You don't really have a big sample size to judge the overall experience. And that's excluding the fact you probably have one common profile (way you dress, race, etc.)