Well, it's vague, but not that meaningless. For one, it refutes the notion that populists' actions are actually what the people want, let alone benefit the people, because populists only claim to act against the elites and for the common people. This means grandparent's reading of the paper that what the people want does not benefit them (at least not economically), because populists only claim to act in the interest of the people.

As a side-note, it's interesting to see that their data shows that populists generally stay in power twice as long as none-populists and they are often removed from office in "non-regular ways".