The cause of what? Evil or calamity, because they’re not the same thing. That’s why we don’t do verse theology, sir. We read the entire context like big boys wearing our big boy pants, so, what does Amos 3 teach about God bringing judgement against wicked nations?
The Bible doesn’t teach God goes off half cockeyed,
“taking a lead role” to help destroy nations at random or on a whim, initiating their ruin without a thought as to their behaviours. In fact the opposite is explained, God
responds to the sinfulness of people and places
(e.g. the canaanites, Sodom, Israel,) after which there’s judgement.
Verse 1
Hear this word, people of Israel, the word the Lord has spoken against you—against the whole family I brought up out of Egypt:
Verse 2
“You only have I chosen of all the families of the earth; therefore I will punish you for all your sins.”
Verse 6
When a trumpet sounds in a city, do not the people tremble? When disaster comes to a city, has not the Lord caused it?
Verses 13 & 14
“Hear this and testify against the descendants of Jacob,” declares the Lord, the Lord God Almighty. “On the day I punish Israel for her sins, I will destroy the altars of Bethel; the horns of the altar will be cut off and fall to the ground.
Well, you shouldn’t call other people’s God fraud, that’s naughty.
Perhaps the eternal decree is imbalanced.

Still that’s not the sort of thing you can complain about, who are you O man to talk back to God, God and his eternal plans to infract you