Actually, a lot of the damage to noses was intentional, and done by many different invaders over many centuries. Notice that the intact ears are also weak points, because yes that was a logical explanation, but the Egyptians were very skilled and experienced after many centuries over carving monumental statues. It may take five thousand more years, if no vandalism or big earthquakes hit the region, for the ears and remaining intact noses to crack and fall off.
Napoleon's soldiers got very bored in Egypt, bitterly hating the hot weather and strange food, and were hardly above target practice on ancient monuments of all descriptions. They were also not exactly enlightened on issues of race, either. I doubt anybody tried to really push that ancient Egyptians were Europeans, though.