This is their definition of “High Risk Application”:
any product, device, component, or system which if it fails or is interrupted, may result in loss of life, or other serious or catastrophic personal injury and/or substantial financial or commercial or societal loss.
So its not just safety-critical applications, it also includes "societal loss". What does that mean I have no idea. Does losing Twitter client leads to "societal loss"? You can argue both ways
Only a court of law can determine what that means with certainty, as written anyways. They might even determine that it’s invalid! At which point they’ll just sever the agreement anyways, and until nullified or upheld it serves as a form of uncertainty gatekeeping.
I cannot possibly imagine what motivated them to put in a “no edgy apps” clause and then post it on a bleeding edge site like HN. A job’s a job, I suppose.