"Cakeism" as a model for public policy

I was introduced this week to the concept of "cakeism" -  as in "have your cake and eat it too" - which is used to describe politicians who see no problem with wanting, or believing in, two totally irreconcilable things.
It is most often applied to Boris Johnson, and the pro-Brexit movement in general. This probably dates back to Johnson's 2016 witticism, "My policy on cake is pro having it and pro eating it", which works fine as a witticism, but less so as a model of public policy. It pretty much sums up Johnson's impractical, populist, pie-in-the-sky brand politics.
It is perhaps worth pointing out that the phrase "have your cake and eat it too" only dates from the early 19th century (the Duke of Wellington is supposed to have used it after the Battle of Waterloo, for example). But it is actually a misstatement of a much earlier phrase (recorded in the 16th century, from the hands of John Heywood and Jonathan Swift among others, but probably in use much earlier than that), "to eat one's cake and have one's cake too". Which, when you think about it, is a more logical description of irreconcilable ambitions than the later, reversed, version. But maybe that's just being pedantic.