Well, perhaps, but I worry more about the complacency of those who are dismissing the risks out of hand. In practice the worst-case scenario will never be even tested, and more likely is just that growth in the next few years tends to flatline or be depressed from what it could have been.
But the risks of a disorderly, no-deal, messy car-crash of a Brexit shouldn't be underestimated. I don't see it as an excuse to just accept whatever deal is thrown at us but at least let's try to make an informed decision about the future of this country, and by definition that *has* to include discussing possible economic impacts.