It's a valid question. If there were crazy homeless drug dealing drop-out trash hanging out in front of my office building, begging for money every time I passed by on they way to my car, it'd be unsettling.
Asking about why a given location is the correct place to put them is not a valid question. Unless of course you're a sociopath who doesn't actually care about the well being of anyone other than yourself...
This is a rather standard gentrification wedge issue rhetoric being regurgitated without understanding the background. At least the PR people got to him this morning to start working on fixing the damage.
He should have seen 5th/6th and mission in the 90s! Not to mentioned the tenderloin during the same period.