However, if even the people who claim we can use "rationality" to determine where to donate, cannot actually agree on what action is rational (as you say, lack

However, if even the people who claim we can use "rationality" to determine where to donate, cannot actually agree on what action is rational (as you say, lack of consensus), then this puts the whole movement into a question. Like, try to put money wisely into charities, duh, as if I didn't know! (Personally, I don't believe in utilitarian rationality. You cannot separate desired outcomes from personal values.)