Because I deplore what the tories have done to the welfare state, our libraries, our medical professionals, our police force etc etc.
I think we should look after people less fortunate than me, I think everyone should have access to a good education whatever their background, I think the state should take back control of public services and utilities so services aren't compromised by the profit motive - and I will happily pay higher taxes for all of this.
Corbyn, for all his flaws as a leader, launched a manifesto that offers a clear choice. It's the most left wing campaign since the early 80s and though I doubt he'll win, I feel compelled to vote labour for the first time since before the Iraq war.