One thing that strikes me is how Conservative members venerate their past leaders and their achievements, minimising their errors. Thatcher and the poll tax would be a good example.
Every Labour PM (and I do mean every single one) has been criticised by the Labour membership.
See this on Attlee:
https://capx.co/its-not-just-the-labour-left-that-has-lost-contact-with-reality/
Tony Blair is Labour's most successful PM ever. Yet many in the membership present those 13 years as a period of unmitigated failure. Richard Burgon did this repeatedly on election night.
Wilson, Callaghan, MacDonald, Brown.
Until we in the membership (and I include myself in this as I was guilty of this) actually present to the voting public a view of Labour in Government as positive, why on earth would people vote for us? If we present Labour Governments as disasters, then surely the electorate will think the same?
I do not mean to avoid all criticism of ineffectual policies or mistakes or worse, but it seems our main praise for our past Ministries is that we created the NHS. Which now happened 71 years ago, and which only came about through what I can only describe as Nye Bevan cooking the books and hiding the fact it was unaffordable.