That makes me think of something else. There are two different types of people who are good at playing strategy games: (not mutually exclusive)
Experienced: People who are good because they have played the game for long periods of time.
Skilled: People who are strategically minded and who are good at forming strategies and at countering enemy strategies.
Many players are both experienced and skilled, however there are people who have one but not the other. The one that I am making my point towards are the experienced players who are not necessarily skilled. These are players who have simply played enough to know the common tactics that other people have thought up for them. When someone does something new that is effective, they tend to label it as "cheap" and "unbalanced". They whine instead of devising a counter-strategy like a very skilled person would.
Of course, this is all my opinion.
Edit: I would also mention that in real life, the enemy may use any strategy they want to use, even if it is considered "cheap" or sometimes "immoral". Think of the imfamous poisoning of the water supply. Another thing to think about is that if you don't like a particular aspect of a game, maybe you should go find another game instead of whining about it.
