A countermeasure is a step you take so that someone else's action — or some danger — cannot hurt you, or hurts you much less. The point is not 'doing something nice'. The point is blocking, slowing, or answering a harm. Governments talk about countermeasures against attacks, spies, or disease. Factories talk about countermeasures against accidents. News English likes the word; kitchen English almost never uses it. You would not call putting on a coat a countermeasure, though actually it is the same kind of idea in easy clothes: a step against a problem. 'Measure' here does not mean size. It means a move, a plan, a thing you do. People sometimes stretch it to any 'thing we did about that', even when nothing was really being stopped.