The author is implying that the rationality of voting for Trump was, for his supporters, strongly dependent on the subtleties of their perception of the distrib

The author is implying that the rationality of voting for Trump was, for his supporters, strongly dependent on the subtleties of their perception of the distributions of outcomes for electing each candidate. An alternative would be that Trump offered an objectively superior outcome for those constituents, in which case only highly delusional perspectives on the outcome would suggest an alternate course.