Not just populists: many groups have less concern for the truth across the whole political spectrum. Example: feminists and their claim that women make an ever decreasing amount of money relative to men. This claim is based on a single study that compared sweeping aggregate data, and then called the whole thing an actionable issue.

The problem is that when you get into the weeds of the claim, and you should always do so, you find that there are so many confounding variables that went unaccounted for that the study cannot reasonably conclude anything. Meanwhile women have been graduating at higher rates since the 90s, younger generations of women make more money on average than men, and women have more job security than men. Women also get substantial benefits throughout their education and are considered a minority class for the purposes of hiring in many jurisdictions.

Be wary of people driven by agendas, even (or perhaps especially) the agendas you think are good.