How much worse is burning Korans than burning US flags, or is it?

Is burning (or defacing in any other way) Korans worse than burning the US flag? Though both acts are protected under freedom of speech or expression because the Koran represents a religion (and one that transcends the borders on the nation) and not merely an institution such as a government that makes it worse burning Korans? Just because the burning of Korans is legal under the law should it logically be avoided because of the potential to incite some Muslims to violence against US citizens or the military of the nation where it happened as if the US sanctioned it or OKed it by not shutting it down?