Oh please. He's not speaking a dialect, he's not using zulu words to describe food (Phutu for instance would be the equivalent of saying taco), he's mocking a dialect based on his stereotype of a people group he's quite probably never met.
He's role playing and I don't think what he's written is intended to offend, but you're being intentionally thick headed if you don't think mocking someone's accent can be offensive.
And before you say anything, no I'm not in a college dorm room, and yes I do live in Africa. I do not speak English with an African accent, but many of my friends do, and don't like being mocked. Ubuntu may be zulu in RL, but odds are he's a white kid in college having a laugh at the brown people who talk funny. There's a perception of implied stupidity when rich white people pretend to be African and type in silly broken English.
He's RP, and he's quite witty, we should enjoy it and he should post how he wishes - but let's not mock KenoCore for perceiving offense where it's quite natural to do so.