He's taking the position of "respect the original result, try to make it work, offer a 2nd vote on the final outcome". It's really not hard to understand. If you're honestly assigning as much blame to the person who is taking that position as you are to the people who:
Came up with the stupid idea of the referendum in the first place & put it in their manifesto, failed to meaningfully plan for brexit winning, completely lied about what brexit means on a repeated basis, mislead the country on whether no-deal was likely, spent 3 years fecking around and subverting democracy, and loads of other things I can't be bothered listing because if you've been paying any attention at all you should be already aware of them.
If you honestly blame Corbyn as much as that lot, then I can confirm that you are a complete idiot.