This particular set doesn’t make the rounds on Tumblr much, probably because it’s a bit darker in tone - I think it drives the point home a lot better.
Why is the white person in there………
Based on the costume, I’d say the white person is a southerner in the US. White southerners are often depicted as racist, homophobic, stupid, incestuous, overly-religious rednecks. It’s not a stigma that is nearly as harmful as the rest of the ones depicted, but it’s still a rude and inaccurate stereotype of a culture, which is probably why they chose to put it in there.