This t-shirt is just a little bit unkind. We can see just by looking at this woman that she's very attractive, and very confident. We don't really need the added extra of her wearing a t-shirt that makes the rest of us feel bad just because we don't measure up! Not all of us are blessed with natural beauty the same way she is, and not all of us have the time and money to spend in the gym to achieve a body like that either.
She'll only be able to wear this t-shirt for as long as she's able to maintain her looks, so perhaps we shouldn't be too hard on her for making the most of it while she's young and beautiful. We can't promise that we wouldn't be this smug if we were this good looking, so we shouldn't hold it against her.