When you are defending yourself against someone you have to pay attention to both the left and right hands or you are going to get bashed.
Yes there has always been anti-Semitism on the left and on the right and at this moment the left is the ascendancy thanks mainly to the Internet where they can communicate and reinforce themselves.
But the character of the attacks is the same, they throw everything but the kitchen sink at their target. If there is one major way to determine whether the anti-Semite is left or right politically, it is this, the leftist pretends to love all humanity except the Jews and so they can embrace Muslim extremists and even Idi Amin, whereas the rightist has many targets and if fact because they did so well in the past, killing the 6 million, the Jews may not even be their main obsession at this moment.
There are different kinds of anti-Semitism from the affluent golf club that won’t accept Jews as members to ranting clerics to skinheads. The greatest danger comes from the most highly educated. Three of the four commanders of the Einsatsgruppen had PhDs. They can organize things to make trains run on time.
Before the Nazis, socialism as a matter of principle opposed anti-Semitism. The Nazis through their name National Socialism made it possible for leftists to retain their anti-Semitism and feel they were part of a leftist party and they rushed to join. That wing was pretty well crushed as they went along. I wouldn’t place too much stock in labels. Labels can be changed but the poison in the bottle is the same.
Untrue. Read Why the Jews? by Dennis Prager and Rabbi Joseph Telushkin. They document not only the anti-Semitism of the "enlightenment" but also the historical anti-Semitism of the Left (with some minor exceptions, such as Saint-Simon) from its very inception. This includes proof that the idea of an "International Jewish Conspiracy" was first hatched by the Left to the Socialists' condemnation of both "anti-Semitic and philo-Semitic agitation" during the Dreyfuss case.