5150 holds are a minimum of 24 and have no maximum. Not 'just' 24 hours. You also have to prove the conditions that caused you to be admitted arent going to happen immediately, which is impossible if you're homeless or were made homeless by your confinement.
To your escalated comment... No shit. That is actual reality and actually what happens. And has been happening. And will likely continue to happen. Even more than non medical prisoners, those forced into hospitalization have such a significantly higher incidence of being assaulted that it's pretty much the same as explicitly damning them to it.
And to your third point, that's my point. Its not just going to be used on the unsightly or dangerous, it is an indefinite hold where you have to prove a negative to get out of; one that has extremely low standards to apply, and one that is applied by people that objectively are not trained to make the determination.
The source is the fucking article you're commenting on, the one that explicitly states being homeless is a mental illness, being unable to procure food legally is a mental illness, and that all first responders, i.e. cops that are absolutely not trained to deal with mental illness, are the sole arbiters of who gets these holds now.
You're as much of a freedom advocate as Ronald Reagan.