I was not very happy with the Left even  before they became Anti-Semites. The reason was simply because their values were against Torah.  Good examples are private property, abortion. Dr. Kelley Ross thinks the Left is Satanic. See this essay: http://www.friesian.com/satan.htm. I would not go so far because i think Leftists were at first idealist and as Nietzsche did they saw the abuses in religion and of princes and kings. Maybe not all. But a lot were simply interested in Justice and were upset with the abuses they saw in the System [in Russia and the USA.] And as Bezmenov pointed out, the KGB did not need to create Leftists in the USA. They were already there. They just needed to give them a little extra help. {I can not go into this here. See his long lecture on Utube}