> Can you tell me why it is difficult to fix the projects and ghettos?
Because “the projects and ghettos” aren't a statement of a problem, and to the extent that there is an agreement that there are problems around those things, there is not consensus on what the problem is, much less the solution, and the lack of consensus is not only about empirical fact, but includes a fundamental clash of ideological principles.
This is correct. Everyone pretty much agrees that these areas are a symptom of a problem. Nobody agrees on what that problem even is.
Further, various factions (there are more than two) seem to believe that the problem is exacerbated by what other factions believe to be a proto-mitigation. E.g. see discussion of rent control -- some people believe that rent control keeps people out of public housing, others believe that rent control forces people into public housing, still others believe that rent control has nothing to do with it.
Because “the projects and ghettos” aren't a statement of a problem, and to the extent that there is an agreement that there are problems around those things, there is not consensus on what the problem is, much less the solution, and the lack of consensus is not only about empirical fact, but includes a fundamental clash of ideological principles.