They cause disproportionate damage to cities and the cause of aiding homeless itself. It's asinine to conflate the two issues and waffle back and forth between "more houses" and nimby name-calling. Neither will help.
We should have 21st century asylums and more houses. I won't accept a false choice, we can do both. (I'd argue we also need subsidized job relocation programs so people don't get stuck in high CoL areas looking for minimum wage jobs. There are very affordable areas to live in USA that want workers, let's make this market more efficient).
But whatever you gotta tell yourself to excuse the mistreatment.
This isn't about American exceptionalism, because either A) other countries don't have this problem (great!) or B) they do and all the "do it like they do" was just proven wrong as a solution to both the problems or C) they did have this problem and it was solved by these policies - great! The immediate intervention of getting the worst offenders off the street is a temporary solution and housing policy wins long term.
But no matter what there's no reason to push back on two heterogenous solutions because it includes more than just your favorite one.
Like common, this does not passes the smell test. When housing is cheap, mentally ill can pay housing and have easier time getting support to get that housing. Their mental health issue do not escalate so quickly due to lack of sleep and constant danger.
Giving a locking door to an addict is a death sentence. As countless experiments have proven, unsupervised shelters all over California have been literally destroyed by addicts and the mentally unwell. I'm talking faeces on the walls, blood and urine everywhere, horrific attacks in the units, and eventually the place just gets burnt down. So these people need supervised shelter. In a facility. Where they're prevented from harming others and themselves. De-institutionalisation was a huge mistake. There were abuses and they needed reform, but throwing schizophrenics and addicts into the street was not kind or humane, and leaving them there is just as immoral.
Weird.