Corbynshite

Corbynites and Momentum can go on about policy till there blue in the face, they still miss the point that the electorate hates Corbyn, no matter how many quite sensible socially progressive policies they put forward looming large over them will be Corbyn and his ilk.
What the voters see with Corbyn is a pathetic whiney little man who could not organise a piss up in a vegan brewery.  He is also a charisma black hole, with no hint of leadership ability, that no one outside of his cliche can imagine as PM, he would be as out of place as PM as Trump is as President.

Let me list the problems.

Pacifism

This as far as the general population is concerned is a weakness, if you have views and beliefs then you should be prepared to fight for them, as a private set of views very few will see them as a major fault however when it comes to a Prime minister, then it is a disbar. If through some accident or misfortune you end up a hostage of some warlord or tyrant in the middle of nowhere, then you don't want to find that the PM has moral objections to sending in a bunch of highly trained heavies to get you out. If someone wants to sign a note and opt-out of any use of violence to rescue them, then fine.

AntiWest

For all its failing western civilisation has achieved a lot, you might think the poor are hard done by but there is no one who would find their standard of living or life expectancy any better 100 years ago but Corbyn reeks of disdain for the west.

Iraq

While he may have been correct about the mess of the Iraq war, we don't know for certain that through some unforeseen set of circumstances it might have been worse if the war had not happened. Corbyn's objects to the war were not based on the specific set of circumstances of the war it was part of a blanket objection, which given that others are prepared to start wars, is not a vote winner.

Competence

The first year of his leadership was a mess and it hasn't got much better. With the Virgin trains stunt, only a moron could have made such a hash of it. He and his team seem incapable of understanding that if you attack anyone, justified or not, they will defend themselves. This inability to see that others will look after their own self-interest rather than just roll over is something Corbyn shares with the brexiteers and the likes of Farage. The empty-headed love some Kippers have for Farage is mirrored in the Corbynites love of JC.

Brexit

His performance in the Brexit campaign was abysmal. His decisions to impose a 3 line whip to support the government line was bad, but to make it even worse he, later on, managed to condemn the everything that 3 line whip had been put in place to support. His varying position looks very much like political expedience on a moment by moment basis, as if by support a point of view half the time and opposing it the other half of the time will result in him being supported by both sides, it will not it will end up with the support of none.

Blair

The constant slagging off of Tony Blair and the Blairites is very counter productive but it is about the only thing that unites the Corbynites, but even if Blair had only achieved 1 thing it would be more than Corbyn has achieved, he has been a disloyal back bencher for years and Blair achieved more for the poor the Corbyn ever has or will, see.

Hypocrisy

Corbyn hold the record for the most votes against the Labour leadership, that he and has supporters go on so much about the disloyalty of others is just pathetic hypocrisy and obviously so, watching his supporters twist and turn as they try to defend the abuse heaped on those who do not follow "the leaders" will is galling.

Corbynites

The biggest area of liability is his supporters, they are just appalling in general. The more they behave like themselves the more they make him unelectable.The average Labour voter is appalled by them but the Corbynites are only interested in themselves, they have no idea whose votes put Labour in power and whose votes lost Labour power.

Len McCluskey

Gobshite.