Leftist reaction is a counter-reaction to the racist, mysogynistic and anti-gay attitudes that was the norm. The rightwing never fully abandoned these attitudes. When the Civil Rights Act passed and America became more progressive the Rightwing didn't just call it a day, they kept opposing progressive gains. Jerry Falwell started the Moral Majority organization to oppose desegregation. Only later did he transition to opposing abortion.
Through out the 90s rightwing talk radio was pushing dog whistle racial politics. Trump became a Republican political darling AFTER he latched onto the racist birther theory. When he thought about running in 2000, no one paid any attention to him.
It's always been rightwing desire to dominate and control that ellicited a reaction from the left and then the right reacts to leftwing opposition. The right - specifically in the South - started putting up most of the statues of Confederate leaders during and after the reconstruction era and the era of Jim Crow laws, because they were angry at losing the war and wanted Black people to know who was boss. Georgia included the confederate flag in its State flag in 1956, a time when Blacks and others were fighting for Civil Rights.
https://www.history.com/news/how-the-u-s-got-so-many-confederate-monuments