The case against laughing is that it makes a leader come off as less serious. This rests on a common misunderstanding that laughter is primarily a response to something funny. Research over the past few decades has backed up what philosophers have said for over a century, which is that laughter is inherently social, more about relationships and communication than jokes.
@corlin Interesting. I know several neurodivergent people (yes, this is anecdotal) and one thing they have in common is that they don't laugh much, or at all. One has a fine sense of humor, regularly cracks up his friends, but never does more than smile himself.
The common factor, I think, is not so much neurodivergence as social impairment. Being the only one who laughs can be as embarrassing as being the only one who doesn't.