Thing is, the whole threatening the victim has always been a part of the phrase. Don’t tattle, don’t snitch, it’s part of the built in bullshit of school, and even teachers and staff sometimes buy into it, indirectly penalizing students that report abuse from other students. Even more common is nothing at all being done to prevent retaliation, so the cycle of it continues.

This is a joke, obviously. They’re turning the idea around, it’s just that the fact there’s an idea to turn around in the first place is so horrible that the joke kinda falls flat unless you have a dark sense of humor.