I do not see how that is a lack of charity. How about we tell things as they are? If you disagree with a Catholic Doctrine, you disagree with the infallibility of the Church and hence, the Church as a whole, really. Trying to sugarcoat it does not make things better, it makes them worse.
But in the situation you speak of, if the Protestants are not Baptized, they should be. If they are, then yes in such an extreme situation they could recieve the Eucharist early. But only if they had been intending to join the Church had they been able to survive.