Look, the explanation is real simple: People don't get taught SHIT in school about the Constitution, the Bill of Rights, or any of the principles on which this country was founded. Those topics are WAY too dangerous to the gummint.
As a result, you have a bunch of folks in America who think "good/right = whatever da gummint says." And of those people, you have many who believe in law and order, and they translate THAT into the following equation:
gummint = authority = law = what is right.
If you want to get technical, Natural Law theory says some things are right/legal now matter what, i.e., rights to life/liberty/property. Positive Law theory, however, says what is right/legal is whatever the gummint says is right/legal. We have been living in a Positive Law world for decades, and that is all some people know.
and, many of those people are attracted to the police and military because those organizations provide the chance to provide the order these people find so dear. This is not a blanket indictment of ALL members of the police or military, just a note that many "law and order" types end up there.