This is true, because the restaurants and other businesses actually have something to lose when they defy the petty tyranny of the city planning bureau. The bureau knows this, and it doesn’t like the idea of losing the power it has, so it comes down hard to punish those who do not kowtow to it.

On the other hand, the heroin addicts don’t really have anything to lose, other than freedom to roam around the city. Since city is not interested in depriving them of that freedom (as jailing the homeless addicts for disorderly conduct would be inhumane, according to San Franciscans), it has no tools to actually incentivize different behavior — it has no punishments left, and so it’s left powerless.