Grandad The Labour Party lost the last election so badly because it failed to realise that the Labour Party is no longer a party of the working class, which feels it no longer represents it and with which it doesn't connect. Something has gone very badly wrong when Bolsover, Denis Skinner's former seat, is now held by a 5,000+ majority.
The Conservatives did not hide the fact that Johnson is an Eton and Oxford educated "toff", who has nothing working class about him. Yet, "working class" people voted for him in their droves. The reason that happened is because Johnson (or at least Cummings) understood them and their values better than the Labour Party did.
The Labour Party didn't just lose the election because of Brexit, Corbyn, the Russians, Cambridge Analytica or the unrelenting press campaign. They lost because the majority of people don't want Corbyn's brand of social liberalism. It isn't Marxism, although the media used that label to frighten people. There is a massive realignment of party loyalties taking place, just as there is in many other Western democracies and Corbyn doesn't have anything to do with that. Social Democracy is in crisis.
The Labour Party needs to stop thinking in terms of social class and reinvent itself to recognise the social values which hold a majority group of people together. Many within Labour won't like the conclusions. Thatcher and Blair both "got it", which is why they were the longest serving post war PMs.
You can go on for as long as you like about right how you are, but the trade unions and certain activists within the Labour Party aren't offering people what they want. You need to start listening to people outside your comfort zone.