Have to admit I read John McDonnell's response as "flannel, flannel, flannel, we'll consult, flannel, flannel." It says something about where the discourse is currently that in the climate of fear and silencing and censorship, this comes across as "brave" and "a breath of fresh air" and "a hopeful sign."
Personally I don't think it's any of these things, and I doubt McDonnell will make good on even that half-arsed promise.
James, I'm going to break with my usual tradition here (because normally I love your stuff), but I think this was a bit on the weak side. McDonnell was asked a huge number of very probing questions, most of which he ducked completely - the economy, how Labour would pay for its policies, Brexit, anti-semitism, past associations with terrorist groups, past advocacy for violent protest - all of which he ducked. And the web chat has resulted in a Jewish poster being banned for pointing out that another poster's comments were anti-semitic.
There's much more of a story out there than just McDonnell's weak and half-arsed mutterings about women's rights (which he hasn't actually said he'll do anything about, just said that he'll consult...).