Usually because they are ignorant, hateful and enjoy tinfoil hat worthy conspiracy theories. I believe Jews are less than 1% of the US population, we've never had a Jewish president or vice-president, so I don't really know what they're talking about.
Most people of Jewish background tend to be succesful thus it leads to generalizations made by imbeciles. Those imbeciles find it easier to blame others for their laziness and lack of commitment to work for their own success. How shameful!
\It means:
The Jewish lobby is VERY influential.
Major media is owned by Jews (as well as hollywood)
Jews are some of the most wealthy Americans and they have tremendous power in areas of Health, finance, law, politics and science