Also guy here, did this as well.
But uh, mainly because I literally cannot get to a haircut place. Been functionally hobbled for 6 months, car got stolen, don't know anybody nearby with a car, no public transit, lyft or uber + a hair cut each month is actually pretty pricey when you are living on disability, waiting for public housing.
Been ordering delivery groceries for a while now, added a buzz trimmer to it this month.
At the rate my hair grows, it'll be back to roughly the length I usually keep it at by the time my PT regimen gets me back into 'normal' shape (probably another 6 months).
So sure, I am in what most people would probably consider a crisis, but it makes practical sense too.
Either way, cutting your hair hair is literally a more healthy way to directly exert what little amount of control you have over yourself... but it is, at least in my experience, far more socially ostracizing than cutting yourself.
Not counting me cutting my own hair, I have know several people in my life who have done both or either of these.
When people cut themselves and this is noticable, people who care at all will be concerned and try to talk to them, suggest therapy. They receive more care and attention.
When someone takes all their hair off? They'll be treated as if they are completely insane, should be avoided and are suspect, and/or are dangerous and should be institutionalized.