When attacks on plans for Brexit are made by the opposition they can be dismissed because it is the opposition, and that is what they are supposed to do.
When the attacks are from economists and experts in their particular fields they can also be dismissed because they are not in government.
When the attacks are from MPs in your own party they cannot be ignored, as May found out.
But when the same ideas are presented as 'new' by 'someone' then to attack them is a conspiracy by Uncle Tom, et al, to derail your attempt to become the next PM, even though those same ideas were found unworkable by the government you were part of, and also by the negotiators on the other side.
Oh, and by the way BoZo, the EU has said time and again that May's WA will not be renegotiated. So what, prey tell, is your shiny new plan that they might, possibly, give you an extension to negotiate, because no-deal isn't it? It will bring you and the Tories down.
About 65 million of us, minus about 160,000 "I remember the Empire" OAPs would dearly love to know.