For some context the episode opens with the humans asking the native american ghost for permission to have Thanksgiving. The native ghost razzes them about genocide and all but eventually reveals he has no issue with it. The other white ghost go through the whole gamut of white guilt. The rich Victorian age ghost says she was an oppressed Irish person so she's not bad. The jewish yuppie ghost says his ancestors were being run out of town during colonial days. The revolutionary ghost is attacked as a colonizer but he claims he is gay, so he should be shielded from criticism.

Then the Viking ghost chimes in about the colonist being genocidal colonizers. Someone points out he had personally killed thousands of people and brags about it still he responds with, "But they were all Europeans so Thor's hands are clean." The tv show is telling white people the death of white people in history is okay.

I know this isn't a new thing. MASH had episodes with Potter defending the World Wars while bemoaning the war in Korea. Making the death of asian people more horrific than the deaths of white people. But there was an implication rather than an overt, dead white people is funny right tone.