I think you should stop and actually look at yourself. You clearly do not get it. No one is labeling all whites as bigots, and if they are they're dumbass crazy fringe extremists.
And no, you don't have to be a racist to defend the Confederate flag, but you are an idiot who is outright delusional about what that flag stands for if you do. And that's the issue. This shooting (which is a separate but definitely related issue) just brought that issue back to the forefront. The reality is, it's been an issue for 150 years, and it continues to be used by racist pieces of shit, because it is intrinsically linked to racism. But there's people who still to this day keep trying to claim otherwise, and go insane when people explain to them how wrong they are. They still try to claim this even though their forebears that they claim they're celebrating by celebrating that flag, outright said specifically that they turned their back on America in order to be able to keep their subjugation and enslavement of blacks. Actually they didn't just turn their back on America they outright started a war over it.
Also, here's the thing, pretending that racism isn't still an issue is blatantly delusional as well. Things have improved monumentally, although the fact that you try to pretend things are fine when its more that things are much improved from when a group of people used to literally own another race is telling. I'd have to ask how old you are, but then I wouldn't be surprised to find that if you grew up in South Carolina they've probably downplayed quite a lot of their history, so it wouldn't shock me that certain things that took place between 1850 and 1970 might be a little fuzzy for you, or that you might think race relations are fine there.
It's just sad that you talk about people minding their business, when you're defending a state that still claims pride in the Confederacy. South Carolina made it the entire nation's business back in December of 1860. And, lest we forget, South Carolina literally started the Civil War. Simply put, in a group of racists, South Carolina was the worst. That's what you need to understand is there is history involved here, and why that's a big fucking deal.
See you added the manifesto. I was like, what the fuck? That's all you can find? Plus multiple people that have interacted with him have said he's gone on crazy rants and said he was going to shoot up a school.