So lots of people still alive today remember those days and understand the danger of politicians like Bolsonaro. People like the current president Lula, who was imprisoned during the dictatorship.
The USA on the other hand, has never had a dictatorship in living memory. It's even debatable whether pre-independence it was a dictatorship, and in any case it is so far removed from the present that it has no impact on everyday life.
Maybe for this reason there is a feeling of "it can't happen here". An exceptional ism that is not unwarranted given the incredible social and economic progress made.
But this attitude is perhaps the most dangerous one can have towards fascism.