meaning of the t-shirt

i think that the boys who were that t shirt not have been expelled. i think that what they did was unintentional. they were wrong in way because they were mocking one of the most tragic events in american hisrory where lots of lives were lost. but then again they were just tryin to show that were indestructable and show pride in there team but it was still offensive but the manner in which the did it was very offensive because there are people overseas right now dying because of that event.