The basic position seemed to be that the EU is capitalist therefore we should leave the EU and create some kind of socialist utopia. Therefore they voted to empower the hard right to take charge and run the country into the ground and crush any protections that workers had thanks to being part of the EU while also tanking the economy that pays workers wages.
Free movement of people is a capitalist idea that lets people come here and 'take our jobs' thus suppressing wages and raising unemployment apparently.
So I guess that their expectation that the UK would continue to enjoy free trade with the EU was based on the "fact" that the EU would be so impressed with the socialist utopia they were trying to construct that they would be honour bound to allow free trade without the free movement of people ?
Sounds as rational as the Tory position that we should have free trade without the free movement of people because we're English* and our moral superiority would compel them.
* - yes I know but quite frankly the Micks, Jocks and Taffies are just an irrelevance - unless they can provide the "supply and confidence"
votes to prop up the government