"My message to [certain segments of] the Jewish community, and all communities, is this simple: the time for warnings has passed. I have instructed the NYPD to proceed immediately to summons or even arrest those who gather in large groups. This is about stopping this disease and saving lives. Period.
Would the above insertion of words make everyone happy? When I looked at the hot spot map, as far as I could tell, each and every one of the hoods had a substantial percentage of orthodox Jews living in it. So it appears that the singling out is data based.
If there were hot spots in black neighborhoods would anyone think a mayor saying something like this about "certain segments in the black community" would be smart?
Singling out any group like that is, at best, counterproductive. You can take the problem seriously without suggesting to people you have contempt for their culture. Work with people within those communities who are receptive to acknowledging there is a problem, and try to accommodate their traditions in a way that reduces risk.