That just means the people flagging politics are biased and inconsistent, not that people don't flag politics.

We know they do. Numerous people have stated outright that they flag every thread they consider political, because they consider all political content to be off topic, and that they intend to continue doing so. And Hacker News is designed so that it only takes a few flags to apply to a thread.

But since you know seem to better, do please enlighten us all on the real answer.