Can someone explain why this is happening?

Boric fucked up really badly and Trump/Local Elites/Social Media have been financing and promoting right-wing ideology in South America in response to the fall of the 2010's Conservative Wave, and the Second Pink Tide (which started with the election of AMLO in Mexico).

are Chileans the gusanos of Latin America or are they just white people?

Chileans can be based communists, cringe liberals or really weird chuds, but that is basically the same for all of Latin America. But the two most conservative countries in South America are Peru (which still do have a large left-wing presence which usually mix with some form of Peruvian nationalism thanks to Gen. Velasco's influence who was basically South American Nasser/Pro-Soviet Social Democrat Dictator) and Paraguay (basically a dictatorship since ever, the country has been controlled by the right-wing faction of the Colorado party since the 1940s, and their main opposition is the left-wing faction within the Colorado Party, who are usually social democrats or socialist christians, and the Liberal Party).

Chilean society is usually very progressive but their economy is really fucked, and it's no wonder there are a lot of protests in there. Kast have been trying to become president for a while now, so most people knows who he is.