Because a large percentage of the electronics stores selling grey market stuff out of Brooklyn are run by Hasidic jews. Obviously not all Hasidic jews selling cameras in Brooklyn are criminals, but it's generally easier just to avoid them. Similarly, just because I wouldn't pay $5000 for a Rolex on the streets of chinatown doesn't mean I'm racist against asians.

In general I have no evidence that Hasidic jews are any less ethical than any other group of people. At the same time there appears to be an ongoing problem of the ones in Brooklyn using their appearance of religiosity as a cover for committing crimes, especially related to selling stolen electronics and drug dealing. (Jesse Eisenberg was recently in a movie called Holy Rollers, which was about the latter problem.) Sure there are some people who are losing business due to being falsely stereotyped, but it's like 200 people as opposed to 200 million so the social consequences are fairly limited.