[tghw]

68% tested positive at a clinic in one neighborhood. Getting tested, without proper controls, is highly subject to self-selection bias. People were sick, couldn't get a test at the time, want to know if it was COVID, go in for an antibody test later. The people who were healthy, unless selected for a prevalence study, would much less likely to be tested in the first place.

Even in your first link, the highest percent positive is the Bronx reporting 33%. Not sure where you're getting 51% from, but it very much seems like you're trying to cherry pick data to support your argument.