Replacement for Confederate Statues

I imagined that there must have been American Military Officers who were from the South but refused to betray the Country that educated them, mainly at West Point, and nurtured their careers. Frankly I had never heard of this guy, who was one of the leading Union Generals.

 https://en.wikipedia.org/wiki/George_Henry_Thomas#Legacy

why do we need to replace them at all?  I'd prefer to leave them like this.  White southerners want to preserve "history"?  Well let's preserve it, including these depictions of the anger of Americans in 2020 toward these monuments to white supremacy.