I agree with plenty of that sentiment and you assuredly raise some good questions there about those particular folks.
Aside from those folks though, (who sound like they would rather be hustlers) the 'why do they not work' question is of course complex and folks seldom consider the factors of:
There are often no showers available... no support from friends or family... no one to watch their belongings while they work... and not having an address or actual phone number... makes things extremely difficult. Then of course there is a lack of public transportation which as you know is in short supply in many places even if it is available there in Cobb county.
Those are by no means justifications or anything and I am simply saying that the 'barriers' to employment are massive and often dismissed out of hand.
As I often tell folks: Go spend a month being truly homeless (destitute) and find out what it is really like.
I am not saying that to you per say (because as you stated you know the challenges involved) but honestly most folks are so far off the mark with their sentiments towards the un-housed that it is easier to de-humanize and/or dismiss them.