Yes. It is as appropriate as Nazi jokes during WWII.
The joke makes fun of the Muslim extremists and terrorists, not the peaceful muslims who are not seeking martyrdom by flying planes into buildings.
These terrorists are the enemy, just like the Nazis or the Japanese during WWII, and the American's ability to make fun of their enemy during times of war is a tradition in this country, dating back to the Revolutionary War of Independence from England where we made fun of King George and his cronies.
Even now we make fun of King George and his cronies....no beating around the "Bush" on that one.
