We had a problem with vagrants long before legalization of pot.
These wandering hordes, and their extensive semi-permanent encampments, are impacting property values, putting pressure on police budgets, and straining local community social services.
It bears repeating: you can either pay to imprison addicts for drug convictions, or you can pay to jail substance abuses for vagrancy. Either way, the net-net cost will be approximately the same. Or, you can let them wander the streets, depressing values, and putting an indirect drain on economic activity, the total (imputed) cost which will also come out about the same as the criminal justice option (ie jail or prison).
FR tends to get into these juvenile spats, as if it's a moral question where one can claim a morally superior position, when it's really just about financial decisions. It really is quite simple: does society want to cover the costs of keeping the streets free of addicts or not? Just note that the costs of keeping the streets free include encroachments on *everyone's* civil liberties.
Or, is the sight of groups of homeless sprawled out in filth and squalor, of bum fights and arguments, of debased street side prostitution, all too much of a visual burden? Think about what events led us to our current state back in the 1920s. Every generation thinks their experiences are unique, but societies have had to deal with this same quandary since governments were formed 1000s of years ago.