You normally only hear jokes propagated if they're funny. You have a selection bias.

funniness is about the couple sender/receiver, not an intrinsic quality of the joke.

One type of the jokes derive their fun from an unexpected twist. The fun is the surprise.

Another type of jokes reaffirms what the listener already believe. The fun is the comfort of being proven socially right. This was the second type of joke. Those are obviously only funny to those who believe in the cliché the joke is using. As Homer Simpson put it "It's funny because it's true!"

(explaining jokes is not funny)

I found it funny (though I stopped using Linux some time ago, maybe that is the reason?)