The option were 3 moderates at the time, and the feeling amongst many supporters was that a) moderates kept losing heavily in general elections and b) the public were mightily peed off with moderates and the centre ground. If you keep losing elections with moderate candidates, why make the same mistake again? Don't you think Labour performed better in the 2017 election with a much stronger and popular manifesto?
Would personally be happy to see a leadership change as long as we don't revert to centre right as I think the last 40 years have shown where that leads, and clearly people want change. Unfortunately, in my opinion, they have been led to think that Brexit will be the change that they are looking for. I think, when immigration from the rest of the world, increased by free trade agreement visas from other countries we deal with starts spiking. But that's another story