No, nobody ever says “I’m going to higher you” as a way to indicate they are promoting you. Not in the military, not in non-profits, not in the government, and not in any private or public business in the US.
“Higher” is a homophone with “hire” and “hire” already has a critical role in reference to career management.
At this point I can only assume you haven’t worked somewhere where English is the spoken language.
Also, saying some vague shit and then claiming it as a joke is very convenient.
Finally, police injustice is not a subject for humor. It's no laughing matter. I'm not the one who's not "getting it" here.