Earlier quoted context omitted.
How do you end homelessness, when some percent of homeless people will, if you give them a place to stay, smoke meth all day and make their apartment and nearby apartments health hazards? Many drug addicts don't want to be addicted, and would try to go through treatment if provided. But some are inveterate, and don't want to quit. What do you do with them?
Not all homeless people are dangerous drug addicts.
Drug addiction and mental illness is another story.