There is a massive difference between allowing someone to die for your philosophical belief and not having the money to support the world. If you have enough money to support yourself and your family with some left to give to charity then you should but you have no responsibility over their life because you are not a direct cause. In the trolley case someone is going to die, but your actions have a direct cause on the damage caused.

By following Kantian ethics you allow people around you to suffer because of your inactions. In a situation such as the trolley case, you are morally obligated to let the trolly hit the 5 people because other wise you would be using the one as a means to an end. Yet by not changing the trolly's direction you are using the one as a means to the end of your philosophy. If you don't change the direction you have also caused the death of the five through inaction. How can this be considered moral?