Thanks for the question.
I think the quote you're referring to is actually part of a quote in which I said that some would argue that a referendum would be a good thing. I think there are great reasons to have a referendum, the primary one being legitimacy, but I still maintain that the gold standard, as you say, is a citizens' assembly, in part because, unlike a referendum, a citizens' assembly has an opportunity for the public to learn. There is an opportunity for the public to deliberate, and there is an opportunity for the public to engage in the issue in ways that don't occur in a referendum.
I also would point out, after looking at and thinking about the referendum in the U.K. recently, that it has given me pause, I must confess. That referendum was hijacked by dominant personalities. It was hijacked by mudslinging and by improper characterization of the issues. More importantly, participation was around 72%. If 52% of people voted to leave the EU, 52% of 72% is about 38%. I don't understand how that's a mandate. On the legitimacy front, it seems to fail.
I acknowledge that the idea of having the public have input in a meaningful way is hugely significant. The question is how to achieve that.