I'm not sure why you think that's a prohibition on political content in examples. Lots of technical books have diatribes concerning many things irrelevant to the subject matter.
I read a programming book that dared to have jokes in it once. Gasp! One even talked about DNA and the wagging of dogs' tails. I suppose we've got to be extra puritanical and dogmatic once our delicate political sensitivities become more important than learning something. That way lies progress.