I think a name change would be very beneficial, but also, mass hysteria seems like more than one phenomenon, and at least some of it seems mixed with hyperbole

I think a name change would be very beneficial, but also, mass hysteria seems like more than one phenomenon, and at least some of it seems mixed with hyperbole so unpicking it all might help too. This instance sounds like one the 'medical' variety of mass hysteria, but there's also the psychological version where the only symptom is a panic caused by perception of threat (real or imaginary). I sat through a lunch talk a couple of years ago by Dr Julia Pierce, a psychologist who's a specialist in public response to threat. She had an armful of case studies where people had proclaimed 'mass hysteria' but actually looking at the evidence people had broadly remained calm and made normal choices. For example a lot of people talk about "panic" during the evacuation of the World Trade Centre in 2001 but actually during a lot of those episodes you find people acting fairly rationally, going back to help colleagues etc. or descending stairs in an orderly fashion, moving out of the way for others, etc. The evidence she presented suggested that the conditions that prompt actual panic are predictable and quite constrained. We're less susceptible to it than Hollywood might suggest.