I’m newcomer to the UK, please explain what is the issue K. Starmer x J. Corbyn

[sunshinegrey]

Sorry if it is a dumb question but what is the issue behind the 2019 elections and Starmer support to Corbyn? Why is it still a big deal?

Even Corbyn said Labour will only win because the Tories are hated so much ..
but could be sour grapes ..