Seriously, just clean the streets.
The US has a dearth of psychiatric beds available, with 14 beds per 100k population. The EU for comparison has 69. Experts say you need at least 50. [0] [1].
You have all these people that need help, but have no way of getting it. Add to that the rampant inequality and the high cost of housing and it's no surprise things got this bad.
We need to fix the systemic issues, not just lock up some poor souls that were failed by the system.
[0] https://www.npr.org/2017/11/30/567477160/how-the-loss-of-u-s...
[1] https://ec.europa.eu/eurostat/web/products-eurostat-news/-/e...
I can't even remember the last time I saw a homeless person in Vienna, a city of two million people. The reason it's like that is because we fixed the systemic issues that plague the US. [1]
It's not my view of the world that's naive. It's yours that's overly cynical and that cynicism is holding your country back.
[0] https://www.feantsa.org/download/austria-2017859919493467368...
[1] https://crosscut.com/2017/06/homelessness-housing-crisis-sea...
0.16% for Austria and 0.17% for the US, given my back of the envelope math and a quick Google search.
You sure those systemic issues are fixed?
edit: Numbers I used.
Austria 8933346[0]/15000[1] - 0.16%
US: 330000000[2]/580466[3] - 0.17%
[0]https://www.migration.gv.at/en/living-and-working-in-austria...
[1]https://news.ycombinator.com/item?id=29596289
[2]https://www.census.gov/popclock/
[3]https://endhomelessness.org/homelessness-in-america/homeless...
I have however lived in cities in both the US and Austria extensively and can anecdotally tell you the homelessness doesn't even compare.
If all those numbers are correct, I would assume it's a distribution issue? Maybe there's a small percentage of homeless folks all over Austria, while they're a lot more segregated into certain cities in the US?
The US already has more prisoners per capita than any other country in the world. Is the "throw everybody you don't like in jail" approach actually working?
Eradicate the motivation for behaviour like that - make sure people know that stealing stuff from cars results in a multiple year incarceration with hard work and a bullet for minimal disobeyance (and probably, because we all know nearly none of these people can get fixed, with a goal of destroying their health and physical abilities to the point they really won't be a threat once released).
Also, to where do you propose to "remove" these people forever, and how much would that cost? Is this a proposal for a "final solution"?