About the time that those who were children during the war, and lost fathers, would have become the elders and leaders of the community.
About the time those children rebuilt the klan
Your assumption of a connection, or even overlap, is unsupported.
The normal reasons for a monument, ie to celebrate heritage, to remember historical and/or respected figures,
seems far more likely and reasonable.
If Trump said he wanted to build a statue of, say, some famous US/Mexican war General, and place it on the border to "remind" Mexicans they were not welcome,
under the belief that a statue would "remind them of their place" or some such shit,
you would be laughing your ass off and rightfully so.
Yet you are claiming that is what the statues in question are about.
YOur case is weak as shit.