Whether he's an ineffective idealist or not is irrelevant to the current situation. What is relevant, is whether Corbyn is a *better proposition as Labour leader than any of the Labour right soi-disant "moderates" who fancy their chances.
None of the people I've talked to about him since Friday think he is a good Labour leader. And these are people who hate the Tories and everything they do.
**By which I mean "a better proposition for the people of Britain under Parliamentary Democracy", not "a better proposition for about 100 knobshines in the PLP".
I think you're naive, with your claims about "they are the people". "The people" in this case covers a fairly broad swathe of the electorate, and if your friends are the kind of people who can be won over by Progress soft-soap, then they aren't representative of that "fairly broad swathe of the electorate" I mentioned.
I'm not a Corbynista, but outwith an entirely-new political system, he's probably the best hope for those members of the British electorate who want to put some kind of brake on the effects of capitalism.