Robert E. Lee opposed Confederate statues in his lifetime and had interesting things to say about the Confederate flag as well.
The statues came a few decades later, mostly between the 1890s and 1920s, when people became too removed from the war to viscerally feel its tragic history, and the "Lost Cause" narrative gained in strength.
https://www.businessinsider.com/trump-on-confederate-statues-2017-8#:~:text=Confederate%20statues%20have%20a%20complicated,Caroline%20Janney%20told%20Business%20Insider.
I am from the South and have at least one ancestor buried in a Confederate battlefield. I very likely have other ancestors who fought on the side of the Union -- the war tore families apart, after all.
I choose to identify with the American flag because that is what I am, and because of the awful and hateful ideas the Confederate battle flag rallied troops in support of.