You're absolutely right. But reading this article the author seems to imply a negative connotation by saying you'd be hard pressed to find somebody willing to live in the mission because of "hipsters, homeless and immigrants".
My interpretation of that paragraph was that no single person was likely to be interested in all three of the neighborhoods mentioned because they're all so different.
No, they're portrayed as undesirables. If he had said the neighborhood was diverse, that would be a positive light. Instead he's lumping them together with homeless and hipsters (a derogatory term).