TLDR; H4H, in an effort to grow their public profile, took a federal grant to develop affordable housing in an ill-suited neighborhood with low vacancy rates which in turn forced them to acquire properties from a shady landlord who may have illegally pressured tenants to vacate. Pressure to meet the grant requirements led to disregard of objections raised by concerned parties within the group.
That is the fundamental problem with Brooklyn, though. The vast majority of housing is hugely inefficient. Ugly little two-story apartment buildings where you could have a really nice 5-6 story building instead.