Oh the right are definitely terrified of Corbyn gaining power. Why else would they throw so much shit at him? If he was such a no-hoper they would sit back and let him get on with it. You're correct about Livingstone - he has done more harm than good by droning on about Hitler every five seconds. I don't believe for a second, though, that he is anti-semitic.
I don't see Labour as being "in the gutter". They've just had a massive upsurge in grass roots support. Or do you mean morally? I don't see them as being morally in the gutter either as Jezza is Mr Social Justice and about as painfully right-on as you could get.
"Careerist reasons" refers to the recent Labour leadership race. The biggest purveyor of the 'anti-Semitism in the Labour Party' myth was Owen Smith.
MPs, of course, have a duty to their constituents but first and foremost they are elected representatives of a particular Party. I think MPs like Jess Phillips, Stephen Kinnock etc should take note of the massive shift in the Labour Party since the last GE and act accordingly. I'd happily see them deselected if they don't. Obviously it's difficult for Jezza to demand loyalty as he's never been loyal in his career and that remains one of his biggest weaknesses as leader.
The UK is going to get more right-wing under May. I'm all for more State intervention given the market free for all we've endured over recent years but with May at the helm you just know it'll end up meaning more restrictions on civil liberties and that kind of stuff.