Why do these racist comments warrant a warning while others don't?

I’m assuming no such thing. I’m reading this one actual statement exactly as it’s bloody well written.

Don’t you get it? It is precisely what was said that made it racist. And they are not saying the same thing: what’s the link between “no experience with democracy” and “living in the bush”? None.

Your gloss on it is just disingenuous excuse-making for racism. The person you’re defending was painting the vast majority of South Africans as one step removed from literal uncivilized hunter-gatherers, a characterisation that has absolutely zero connection with any reality now, or even in the pre-colonial past.