They hate it because it became a one stop shop solution for everything. (Especially the mental illness problems are troubling without any of the very much needed therapy, continuous follow ups, visits from a social worker, etc.)

that would be a bit more believable were it not for the people who make sure that the "poor apartments" in a building have a separate entrance.

While that makes a great headline, how common is it?

enough to have its own wikipedia entry, at the least! https://en.wikipedia.org/wiki/Poor_door

Which seems to imply that while a poor door is not very common, it is becoming more common in response to affordable-housing regulations (requiring a % of market-rate developments to be affordable).