Why are Brazilian leftists so based? What is in the water over there?

I would say that all leftists are based. But I believe that in Brazil there are many reasons. First, communism and its various forms were very popular during the 1920s - 1960s, then Lula popularized his version of unionism and syndicalism in the late 1970s. Second, because the best presidents were center-left and left-wing presidents, Brazil had its own state ideology similar to Left Peronism called Trabalhismo. Third, because right-wing governments were openly hostile to workers, minorities, and radicals, anyone who was against the oligarchy was its enemy.