Would you vote for Labour in a general election (whether Sir Keir or Andy led the party)?
I think a lot of people on Lemmy support the Greens but I very much doubt that the Greens could stop Farage becoming prime minister. Labour are probably the best-placed party to do that.
Heck, I’m a member of the Green Party and I’d vote for Andy Burnham if he was leading Labour in the General Election.
I won’t hold my breath through - New Labour would rather lose everything than let the left regain control of the party.