TBH I went to egypt once and the Tour Guide told me that the tribes which arrived at the temples, were superstitious about the sculptures looking at them and stuff, and that's why they have most of the faces chiselled away.
I don't think it was europeans, as they were relatively modern when they arrived, around the times of Napoleon. They say they shot off the sphynx's nose because it was negroid, but that hasn't really be proven either.
Consider that many people know Ancient egypt contributed to ancient Greece, which contributed to Ancient Rome, and thus the rest of europe, I doubt europeans would want to destroy ancient Egyptian artifacts.
Also, note the amount of german egyptologists. If europeans are so interested in ancient egypt, why would europeans destroy ancient egypt?
My great grandfather actually used to translate coptic to german.
Speaking of Coptic: According to Wikipedia:
The Copts are the native Christians of Egypt
The Coptic language is the last stage of the Egyptian language.
Christianity is older than Islam. The coptic language is an indigenous egyptian language. It seems that the indigenous egyptians, copts, converted to christianity. Then came the muslims, which now form 80% of the population. Probably those muslims destroyed all the ancient egyptian artifacts.