Isn't it more straightforward (it's there among the 'virtues of rationality' no?) to just not call things 'rational' if they do not involve thinking?

I don't think so, since that would be a trivial property that doesn't indicate anything, for there is no alternative available. Decisions can be made either correctly or not, and it's useful to be able to discern that, but the world is always what it actually is.