Find an example of a serial murderer in modern times locked in a pitch black room.
Oh ... do you think that being locked in a pitch black room for a few hours is worse than being locked up with a bunch of racist gang members who continue their criminal activities while on the inside for several years?
You’ve picked a ridiculous comparison/contrast to hang your hat on ...
and IMHO, you’re drastically missing the point. If you don’t like ad-hoc inappropriate discipline then enable real, meaningful, appropriate discipline. Or enable the simple removal from the classroom of incorrigible troublemakers.
I seriously doubt the that children who got locked in the boiler room were perfect, innocent little angels.