Turns out people have little sense of humor around shooting kids, go figure. It's about as safe to joke about as telling the stewardess about the bomb in your carry on. Just as personal tactical advice and not civil rights commentary, better to joke about scenarios where people have greater than zero tolerance.
That also leaves out Meta, Google, TikTok, X, etc. They all have policies to hand over data without a warrant for posts classified as CSAM, terrorism, self-harm or threats of violence. They have law-enforcement portals and a 24/7 emergency-disclosure process. They are protected from resulting liability by the Stored Communications Act. I wouldn't be surprised if their humor detectors are no more forgiving than SnapChat's.