The Labour party and Labour voters are 2 totally different entities.
The advent of Momentum, and the election of Corbyn as leader, took Labour to places that ' traditional' Labour voters did not want to visit.
I agree with all you say about Johnson, but people obviously thought he was the 'lesser' of 2 evils.
I don't often agree with
@davek, politically , but he was right about it being 'the Brexit election'.
Corbyn's performance during the Remain campaign was dreadful, and Labour also immersed in the ongoing 'anti semitism' scandals looked like a party at war with itself.
I have been a Labour voter all my adult life, up to Corbyn and the last election, in which I voted Green, other people obviously went over to the Tories.
I fear that Labour will remain in the political wilderness for many years to come.