You're right. It's not vandalism. It's crime. But we misunderstand each other.
Just so we're clear: the song lists a bunch of crimes that would be punished in some way, in a small town (presumably extrajudicial).
The exception is the flag being burned, which the author considers a crime, I assume. Or worthy of punishment.
The part about a gun his granddad gave him, is the fear of it being taken away (by law). I wonder how effective such an heirloom is
You mention KKK but that's about race, right? I don't see that in the lyrics. Unless crime in general is synonymous with black people in the US.
I also don't see lynching mentioned. You're American, I assume, so you can better interpret the implicit messages.
The song is definitely a threat, no doubt. I certainly don't condone any of it. But it's art and you can sing about killing cops and all sorts of people.
I still read The Guardian