This is an extremely disingenuous guilt-by-association argument that groups together "generic conservatives who gripe about billionaires financing their political adversaries" with "anti-Semitic nutjobs".
There are anti-Semites in many movements, both left and right. Louis Farrakhan has been openly anti-Semitic for years. Jesse Jackson has referred to New York City as "Hymietown". Should we dismiss the entire black civil rights movement as "crowds with a distinctly anti-Semitic streak", or should we condemn Farrakhan and Jackson personally while acknowledging that not all of the people they work with share their most repugnant views?
Should we dismiss the UK Labour Party as a "crowd with a distinctly anti-Semitic streak" because of Jeremy Corbyn's uncomfortably friendly comments about Hamas?
Let's also not miss the facts that (a) much of the criticism towards Facebook has been directed at Mark Zuckerberg personally, (b) Mark Zuckerberg happens to be Jewish, and (c) there is also no shortage of anti-Semites who make the connection between A and B. But, because it doesn't serve the media's vested interests to protect Zuckerberg the way they protect Zuckerberg's critics (remember that Facebook is a direct competitor to the mainstream media), they don't go out of their way to point out this connection.