They are not talking about blacks.
From the recording:
“If it was back in the day, when that when Alan Marshton would take a damn black guy and whoop their ass and throw him in the cell? I’d run for f***king sheriff.
Sheriff: Yeah. Well, It’s not like that no more.
Jennings: I know. Take them down to Mud Creek and hang them up with a damn rope. But you can’t do that anymore. They got more rights than we got. “
Probably covers everyone who breaks the law. My ignorant question is: Where is the first amendment in this conversation?