Not sure what picking out some random image really proves? You could pick out images of people who are not a 'future soldier' holding a poppy too, it doesnt really mean anything.
Its not a political symbol, its not promoting religion. It can be used as a political symbol but so can anything, any image can be used by someone wearing a tshirt, I would imagine then you have football players heading out onto the pitch stark naked to avoid any sort of political statement (given the England kit itself is st georges flag based and that has been used by far right to promote political aims).