"His lost election that he bizarrely sees as successful seems to have gone to his head."
I still wish I could understand why you continue to plug this line. It's as if context doesn't matter to you, or something. Labour had 232 seats, and looked like they'd be lucky to hold onto 200 of those -- they were clearly in disarray, clearly going backwards, and clearly heading for electoral oblivion. And then the campaign started, and May presided over a "shambles" of a campaign, and Labour were able to make gains -- enough to stop the Tories having a majority of any kind when it was for a long time expected that majorities of 100 or greater were well within reach.
So yes, Labour lost -- but to pretend that this is somehow the only part of the story that matters is a remarkable conceit. They shouldn't have merely "lost" -- Labour should have been crushed out of all existence and given no chance of meaningful power for another two or three elections at minimum. It should have made Labour's 1983 disaster look like a triumph in comparison.
As it is, none of this happened, Corbyn having seen Labour to a much healthier position in Parliament than previously, putting paid to any serious notion that Labour under Corbyn is "unelectable".
In those circumstances -- yes, I suppose he would be well-justified in turning to those in his party who opposed him and saying "get behind me now". That might not bode well for those from his own wing who bashed Corbyn for so long. For my part, I hope he does recognise that yes, it wasn't a victory, and yes there is therefore a way to go to win outright, and that means that he should be prepared to move some ground himself to bring the party together. But the story of 2017 shows that bringing the party together under Corbyn can deliver an electable Labour party -- even on quite a left-wing platform.
Meanwhile, perhaps the Tories should sort out their own house? With all the troubles Labour faced, and the disaster for which they were headed, they couldn't even reached a working majority of any size on their own. It's a pretty poor result. A technical win, yes -- but only with the DUP's help, and only at the expense of almost everything of substance that was in the manifesto.
Context makes a great deal of difference.