You're right to an extent. I absolutely believe in the utility of humour and satire as ways of illustrating certain ideas and forcing people to think. People on HN especially are much too prudish. These forms can be a lot more effective than a long piece of text.

What I mean, though, is that there's only so much information that a piece of humour or a comic strip can convey.

Also, you have to consider the crowd that xkcd caters to, and the crowd that typical American geek humour such as Big Bang Theory caters to in general.

Existentialism/Nihilism are common themes in geek humour, but negatively: these ideas are quick to be dismissed as edge-lording, and as 8-chan-incelling.

Geek culture and morality relies wholly on the self-supporting idea of science as the one and only source of truth. The geek's first reaction will of course be to dismiss any claim to the contrary, in humour and otherwise.