I mean...
1) This isn't the original video, it's a lip sync.
2) It's a "viral TikTok" and you can therefore be 90% sure it didn't literally happen. That's not to say it DOESN'T happen, but you can be pretty sure that this specific example is fiction.
3) One of the first things they say is "they were clearly mentally ill", and ignoring parts 1) and 2) and pretending that this IS a real thing... no, I don't think it's "funny" to talk about or encourange violence e.g. "punching a mentally ill person in the throat" for any reason, it's actually pretty grim. Mentally ill and learning disabled people say inappropriate and offensive things. No one has to accept it or like it but maybe not applaud aggressive language and assault
.