However, I think it truly misses the mark with "the message."
...The Sanctuary Districts aren't examples of what happens when people at large stop caring, it's what happens when governments stop caring....
...Does that excuse the fact that the general public seems oblivious? No. However, I would say it shows that people are under the impression of "well, the government is taking care of the situation, so why should I bother with it." Whenever the government takes over something like this, you get the extreme overreaction of storm the place with guns blazing, and that isn't justified either. Private individuals and groups need to step up and deal with the situation in a humane way...
...And yet, amazingly, the episode never makes mention of the fact that if it wasn't for these government programs the problems wouldn't exist in the first place. No, instead it's the fault of the general public for "not caring."

You get the distinct impression that the episode's ultimate message is that what is needed is an even larger government to come in and fix the problems even though it was the government that caused them in the first place. Intervention wouldn't solve the problem of intervention.