At the same time the Muslims are commanded to exercise self-restraint as much as possible. Force is a dangerous weapon. It may have to be used for self-defense or self-preservation, but we must always remember that self-restraint is pleasing in the eyes of Allah. Even when we are fighting, it should be for a principle not out of passion.
If we can choose where to cry, at home or with a few people who will be fully understanding, perhaps we will feel easier. But if we can't - if we are in church and a hymn catches us off guard, or at a football game and we remember being there with a son or daughter now gone - well, the earth is our home and we can cry where we want.