Many of these were erected by the United Daughters of the Confederacy. This is a white supremacist organization, which contemporaneously defended the KKK. The monuments romanticize the era of slavery and glorify those who fought to defend it. Whatever historical value they have is not balanced by the tacit approval of their symbolism through their prominence in public spaces. This contributes to an overall normalization of racist attitudes which directly contributes to racism. Moreover, their removal from public spaces does not equate to erasing history, and nobody is arguing that it should.
Interesting graph. Civil war ended in 1865, but the peak statue construction appears to be 40 years later. I know nothing about the United Daughters of the Confederacy, other than about anyone from South in that era would be considered full blown racist by modern standards. The biggest spike appears to be from 1900 to 1915. What factors would you attribute it to?
Building of statues around civil right movement could be considered suspicious, I'd support removal of any confederate statue put up in that era. Say 1960 and newer should go. But statues erected more than 100 years ago? To me, that is history.
You also make another logical jump in stating "this contributes to an overall normalization of racist attitudes". You reductive view of the civil war leads you to conclude it was racist vs. non-racists, therefore anyone celebrating confederacy must be automatically racist. The reality is much more complex, with racists on both sides.
I lived in Texas for couple years, I have seen Southern Pride firsthand and don't consider it inherently racist. Both racists and non-racist people show it. Many people there genuinely associate with Texas more than with US. For example, they take pride in the Battle of the Alamo and victory over Mexico. Does that make them anti-Mexican racists?