The homeless people who cause problems are now are, for a lack of a better word, fucked. It would cost tons of money to get these people the rehab, therapy, and education they need to reintegrate into society. It would be politically impossible (and probably financially unfeasible) to implement these changes. A better solution is just not creating these people in the first place. That is what housing first policy tries to achieve.

The vast majority of these people stories are the same - due to systemic poverty issues they weren't able to have stable housing and could not go to school or land a stable job. It was then they started petty crimes like doing drugs/stealing, and once they had a dependency on that lifestyle, they became a regular criminal over 10-15 years. Anyone who tells you they are going to undo 15 years of trauma within the next 3 years is selling you a lie.

What they do after that isn't really relevant to be honest. I'm not trying to polish people into perfect rule following members of society and anyway homeowners get addictions and commit crimes all the time as it is. We don't generally leap to questioning their right to have a place to live though.

If giving homeless people houses solved no other problems it would still be correct and morally necessary.