You are underestimating the type of people this law is targeting. Nobody who is just stressed out is going to be forced into an institution (although I agree the law should be carefully written to guarantee that). This is meant to get people who are full-on batshit insane off the streets and in an environment where they at least have a CHANCE of getting sorted out.
For example, I have a friend who is psychotic. No, I'm not misusing the word or exaggerating, this is a person who is sincerely and obviously psychotic, diagnosed as such by a psychiatrist, sees and hears things that are not there, believes that the government is all rape-demons from hell that are out to harvest our sanity.
When unmedicated, that is.
Once medicated, she is like "holy shit clarity thank god, keep giving me the medicine." But if there's ever a lapse, we go right back to the rape-demons from hell trying to force pills down her throat and the only way to save her is to, essentially, violate her by being the rape-demon from hell that forces pills down her throat. Which is of course very illegal but people care enough about her to do it anyway.
It would be very nice for it to NOT be illegal to save people from the rape-demons from hell, to have a support system in place aside from what is basically a secret cabal of friends and family as a safety net should this person end up somewhere alone and unable to access their meds.
Could still be a real European perspective. I've found a lot of people who are only casually familiar with North America will be able to tell you the broad cultural strokes and then one or two bizarrely specific facts. Like, "Oh yeah, America is all New York, Texas, California, Florida, and who could forget the iconic Egyptian Theatre of Boise, Idaho."