Anti — Semitism is a very loosely defined concept, to Zionists and criticism of Israel is anti — Semitism. To Labour’s hardline , pro — Palestinian left conflating British Jews with Israeli fundamentalism is reasonable. Tha’s an argument for Labour to sort out internally.
As for extremism in the Labour Party, what do you think the momentum group are all about. If you are not familiar with their actions and tactics read this story in left wing newspaper The Guardian.
On Corbyn’s lack of popularity, his track record of supporting extremism speak for itself. His links to the IRA are well documented. His support for Palestinian activist groups is long established with Hamas having been mentioned as friends many times.
I don’t take much notice of mainstream media but I am aware Theresa May has not been treated kindly by them. Whether she or Corbyn is given a harder time again is a matter of opinion. All I can say having studied the full data from polling companies is that Corbyn is the best electoral asset the Conservatives have.
Personally I like the guy, even though I disagree with his politics. But he isn’t national leader material.