Power politics doesn't have to be about doing nasty things. It can also be about threatening to do nasty things.
I detest politicians who claim they want to govern without power politics, because it makes them look like fools. Being aware of and understanding power politics should be important for every politician - because they need to recognize that there ARE nasty things people can do to each other, and recognize that other people will definitely resort to them if pressed, or if that promises an advantage.
It's like during the cold war - there was always the specter of war hanging over everyone's head. Successful politicians, especially those from weak nations, understood how the game worked, what the power-political logic of any given situation was, and adapted accordingly even if they did not (or could not) actually play that game and invade other countries, order assassinations, or fund horrible guerilla movements.
Rejecting something always carries the danger that you also refuse to understand. That's why people should study how power politics works, and put themselves into the minds of someone capable of carrying out such nasty things. Understand the other side and anticipate its moves, and then plan your moves accordingly.
Not to mention war exhaustion meant that people would have trouble backing Churchill in yet another intervention.
