This antisemitism row is all well and good, but it's distracting from the real reasons as to why Labour are unelectable in their current form.
Can there be anyone in this country who does not understand that money does not grow on trees, and therefore, in the long run whatever you spend has to be paid for by money from somewhere? Surely this is a base upon which we can all agree? Yes in the short term you can borrow more and more, but you can't do that forever. In the long run, you have to balance the books. Agreed?
So the only way we get to spend more over the long term is if we generate more tax revenue. The best way to achieve that, is by having a strong and growing economy, i.e. businesses producing, selling, exporting, hiring more. You need a set of policies directly aimed at supporting businesses, helping them grow, provide an environment for them to do well. Unfortunately this is completely lacking from Labour thinking. In fact the likes of McDonnell thinks the opposite. He's quite happy for businesses to do badly since it favours his wider ambition of everything returning to state ownership.
So instead of pro-business policies, we have stuff like increasing corporation tax; limiting the amounts companies can pay their own executives; increasing income tax so employers have to pay their employees more; increasing employment costs with higher minimum wages; employment restrictions such as ending zero-hours contracts; increases on stamp duty for financial services firms.
Irrespective of the moral rights or wrongs or intentions good or bad, these are policies which make it harder for business to do well, not easier. They discourage investment into the UK, not encourage it. At the very time when inward investment is vital since we are already losing investors because of Brexit. It is a set of policies which will ensure that the economy, over time, does less well.
And since the economy would do less well, then tax receipts would fall. The only way to compensate for that would be more borrowing (which we agree can't go on forever, right), or higher tax rates. But increasing tax rates reduces the amount of money people and businesses have to spend on goods, r&d, hiring people etc. So this depresses the economy further.
It is an inevitable downward spiral until the economy is so borked, people are so pissed off, and Labour get kicked out. This is the inexorable fate of every Labour government. It is no coincidence that Labour ALWAYS leave office with more people unemployed that when they came into power. It's not down to "bad luck" - they are too consistent at it for it to be luck. It is a direct consequence of them following the wrong policies, every time.
The only exception I can think of who really got this was Tony Blair - the most successful Labour leader ever, and arguably one of the best PM's in a long time. He understood the importance of a pro-business agenda. And guess what, he did pretty well, didn't he? 3 election victories, huge increases in spending on the NHS, schools and everthing else.
And now look at Corbyn and McDonnell. What are they going to do to support businesses and help the country grow? Fuck all. In fact the very opposite. If ever elected they will trash the economy and make everyone worse off. This isn't a possibility: it's a cast iron certainty.