Indiana is a bit of a superstitious nut too, not that it doesn't benefit him. He had no real reason to avoid looking at the Ark as it was opened and no logical reason to assume it was dangerous, but he closed his eyes anyway and told Marion to do the same. It feels as though it demands respect for what might otherwise be dismissed as laughable folklore which was the precise attitude held by Belloq shortly before he and his were slaughtered by supernatural powers.
A surprising fact about the most genre savvy moment in the movie (Indiana shooting the swordsman) is that it was originally scripted to be a long sword battle, but rather than having an epiphany of the character's common sense, the scene was shot due to Ford suffering dysentery. I had never known this and had always fell under the misconception this scene was a deliberate deconstruction of the heroic fight scene.
There is also much ado about nothing over the portrayal of Arabs being shoved up our pipes by people with political agendas to serve. The typical skunking comes in the form of "the Arab/Muslims are portrayed as violent and ignorant." However, the first Muslim we are shown in the movie is, in fact, a family man, a professional, and a good friend to Indiana. Then there is Imam, a scholar, priest, and astronomer who revealed the secrets of the medallion to Indiana.