Honestly all those chastising about people voting the tories in are doing no one any favours. That was years ago, when labour was unelectable. In a time when we were still dealing with brexit, no one would say what they would do. Boris offerings were better; in at least that they were clear.
Labour was very clear what they would do. On Brexit, they would hold a people's vote on whether to proceed or not. On everything else - the economy, jobs, public services etc. they had extremely clear and costed plans. I'm not saying their approach (particularly to Brexit) was necessarily the right one, just that it was there as an option for people to vote for it they wanted. They weren't unelectable - they were simply one of the options, which people CHOSE not to elect. (There is of course a huge additional problem in how our first past the post electoral system forces people into a choice far more binary than can realistically represent their will).
The "unelectable" thing is just another way of saying: "Labour were proposing things that were beyond what most people were willing to consider, politically or intellectually". The problem with blaming Labour for that is that it's starting to look like people's inability to exercise that kind of political imagination is a huge problem that is going to fuck us forever (particularly wrt climate change) regardless of what the Labour party do. There is another way of looking at it, which is that people weren't able to face the fact, in 2019, that capitalism as we knew it is dying and is no longer able to provide the majority of citizens with a decent life and trust in the future, and that radical change of some kind is both necessary and inevitable. How many people are willing to face it now?
The thing about forgiving and moving on, in anything, is that it's dependent upon learning the lessons from the experience and moving on wiser. There's are serious problems here with much of the British electorate: they are ill-informed, and lack the will to get better informed. They are surrounded by a mainstream media which functions as a barely disgused propaganda outlet for the Tories, and lack the critical thinking faculties to challenge it. There is a current of underlying racism that makes them amenable to economically invalid arguments from the right.
When I read this stuff about Labour being unelectable in 2019 all I see is people wanting to let themselves off the hook of addressing any of these problems, and continue with the insistance that they should be able to lazily place their trust in who the media tells them to trust, and believe that things will be OK. As long as they keep doing that, they will continue to get the government they deserve.