The problem is they treat populism like it's an ideology. The reason it's possible for two different "populists" to believe wildly contradictory things is that populism isn't an ideology, it's a rhetorical strategy that basically anyone can use (though, right wing populists have to lie constantly).

Elitists conveniently ignore this, which lets them pretend that everyone who makes any reference to the concerns of common people, in any context, is part of the same ideology as Trump/Bolsonaro/some other bad guy.