Examples I've dealt with personally: human shit on the front steps of my building, almost daily. Kids can't play outside because there are needles on the ground. Multiple neighbors' catalytic converters stolen, sometimes multiple times. Stolen cars without license plates. Entire encampments catching on fire. Bikes stolen from locked garages. Neighbors threatened with guns.
Where I live, there's a large part of the homeless population who refuses help from social services and won't go to shelters. I get it, shelters are shitty, but these people prefer to do drugs. I'm not the type of person who wants to call for forced institutionalization, but that almost feels like it would be more humane than the conditions these people are living in today.
This isn't a NIMBY issue, and until you've experienced it right outside your own house, you may not understand how bad the conditions can be.
Stolen property, burglary/robbery, biohazard in the form of feces on sidewalks, and potential unprovoked violence are hardly just "an aesthetic inconvenience" in minds of most people.
As someone who spent some time homeless during the peak of a past heroin addiction, I can tell you that the comment you replied to comes across a lot more grounded than yours.