What's New York's Excuse?

According to Robert Putnam, ethnic diversity makes people less gullible (seen via TJIC):

A bleak picture of the corrosive effects of ethnic diversity has been revealed in research by Harvard University’s Robert Putnam, one of the world’s most influential political scientists.

His research shows that the more diverse a community is, the less likely its inhabitants are to trust anyone – from their next-door neighbour to the mayor.

In that case, shouldn't New Yorkers be more skeptical of liberalism?