When Moses returned to the camp and saw the golden calf, he was furious that they had so misunderstood the nature of an unseen God. That was supposed to be their great contribution to civilization, that the energy of the universe, the power of God did not need physical symbols or images for representation. The ideas should have been enough.
He takes two measures. He smashes the tablets. The people were unworthy of receiving a Divine gift. Then he took the calf, melted it, ground the material into dust mixed it with water and made everyone drink it. I can think of no better way than to show the utter uselessness of the idol. Not only by destroying it but by making everyone drink it in, passing it through their bodies and then inevitably excreting it. From the highest to the lowest.
So much for the god. But what about the people? How many of them were involved? The text says that he saw the people were out of control. He turns to Aaron who tries to excuse himself. He said he was only trying to contain the situation. What was he to do? The Midrash says that Hur who was left behind as joint leader tried to stop them and they killed him. Aaron saw (in verse 5 of Chapter 32). What did he see? How out of control and dangerous they were. He compromised.
Moses takes dramatic action. He rallies the faithful. Only the sons of Levi answer his call, “Who is on God’s side?” They move through the camp purging the ringleaders. Three thousand of them. It seems it only takes a small minority to whip up the masses. But that is followed by another plague but we are not given the final tally.
All this confirms the idea that that it was a disaffected minority, perhaps two groups mentioned elsewhere in the Torah. The Erev Rav, the mixed multitude of refugees who joined the Israelites on the Exodus. Or the Asafsuf, the reeds, the dregs that exist in any society. And yet there is just as much chance that it was Israelites themselves. Because both in Egypt as well as throughout the forty years of wandering, there was a consistent rumbling and grumbling when things got difficult from within the Israelites themselves.
So it is today. Human nature has not changed.