If, as Fr. Dowd suggests, an idol can be thought of as a focus of the god's "real presence," then today's first reading makes more sense to me than it used to.
The LORD said to Moses, "Go down at once to your people, whom you brought out of the land of Egypt, for they have become depraved. They have soon turned aside from the way I pointed out to them, making for themselves a molten calf and worshiping it, sacrificing to it and crying out, 'This is your God, O Israel, who brought you out of the land of Egypt!'"
I never understood why people would think a statue they saw being made was a god. It makes more sense if they thought that the LORD had become truly present in the statue.
God's reaction also makes more sense:
"I see how stiff-necked this people is," continued the LORD to Moses. "Let me alone, then, that my wrath may blaze up against them to consume them. Then I will make of you a great nation."
After all God did to show His power and majesty to His People, that they might know He Is Who Is, at the first chance they get, they reduce Him to their plaything. They tell each other the idol is God, as though they could by their own words make Him become present in the idol. Their offense isn't common or garden idolatry; it's blasphemy, a claim that they control God -- and, by extension, that they brought themselves out of Egypt.
The reading contrasts the Israelites treatment of God with Moses':
But Moses implored the LORD, his God, saying, "Why, O LORD, should your wrath blaze up against your own people, whom you brought out of the land of Egypt with such great power and with so strong a hand? Remember your servants Abraham, Isaac, and Israel,
and how you swore to them by your own self, saying, 'I will make your descendants as numerous as the stars in the sky; and all this land that I promised, I will give your descendants as their perpetual heritage.'"
So the LORD relented in the punishment he had threatened to inflict on his people.
Moses doesn't force God to do anything. He doesn't say, "You can't do that!" All he does is remind God Who He is, Whom He has shown Himself to be to Abraham, Isaac, and Jacob, and to Pharaoh and the Israelites.
You can't control God. You'd better not even try. But you can depend on Him to be Who He is -- which, if you are who you're supposed to be, is more than good enough.