I'm not sure what you guys mean by 'centrism'.
All these candidates have said that they are socialist but want to listen to an electorate that has totally and comprehensively rejected a very far left manifesto and general approach. They have pretty much all said that they believe in slightly more inclusive forms of socialism apart from Long-Bailey who gave Corbyn's utter failure of an opposition 10/10 and wants to carry on with the approach of the last lot.
Surely the point is that there is very clear empirical proof that that approach does not work. Electability is by definition the number 1 priority of a political party and if you are totally unelectable when we have, as Ollie mentions above, a media and electoral system massively stacked against us, I just don't understand the reluctance to compromise and learn our lessons.
'Building a movement' over 15 years while ceding all the power and all the cards to the enemy doesn't make much sense to me as the best way to defeat the Tories. Surely the only way to change things is to get into power and then you are able to effectively shift the dial. You can't do that when you are out of power.
There are clearly people in the Labour movement that are hugely put off by the left wing faction that has been in charge. Surely we want those people in our movement. Not only that but as is said again and again, the electorate don't vote for us as we saw in the North with seats like bloody Bolsover turning Tory! An example from my personal experience is the vast majority of my mates/acquaintances of Caribbean origin (mainly St Lucia, Antigua, Jamaica and mainly first or second gen immigrant) voted for the Tories this election. The Tory party that has been literally violently attacking their community with the Windrush scandal. Yet none of them felt that Labour were the party for them. If that doesn't make you sit up and think for a second, then I don't know what does.
If the movement is not relevant to the people it purports to stand up for, then what is the point of it?