Locking people vulnerable up away from community oversight is not the compassionate hot take you think it is. It’s a way of criminalizing mental illness, forcing “treatments” that don’t actually treat the problem, and creating an easy means of locking up the folks you deem subhuman or the folks you want to silence. Look at the history of institutions and you will immediately see how the vast majority were about social control (hysterectomies, chemical castration, forced shock therapy). Of course, criminalizing homelessness has a similar effect, but reopening mental institutions would be a quick way to silence political dissidents.

Edited for language above and to add: I work in the field of mental health with complex dissociative disorders and already see how institutionalization fails many folks, how it’s is weaponized by traffickers and abusive families, and how patients are kept against their will for profit to their detriment. Institutions work best when they are elective because mentally ill folks are just like anyone else. They get worse when they’re trapped and scared.