You are concerned about the bush, for which you did not labor and which you did not grow; it came into being in a night and perished in a night. And should I not be concerned about Nineveh, that great city, in which there are more than a hundred and twenty thousand persons who do not know their right hand from their left, and also many animals?”
Jonah 4:10-11
The implication being that God does care about pagan cities and pagan peoples, even the most wicked among them. But does a contradiction emerge from this reading when we compare it with statements like these found in other prophets?
All the nations are as nothing before God; they are accounted by him as less than nothing and emptiness.
Isaiah 40:17
All the peoples of the earth are counted as nothing, and God does as He pleases with the army of heaven and the peoples of the earth. There is no one who can restrain His hand or say to Him, 'What have You done?'"
Daniel 4:35
As for the other nations (i. e. not Israel) which have descended from Adam, you have said that they are nothing, and that they are like spittle, and you have compared their abundance to a drop from a bucket.
2 Esdras 6:56
It would seem that whereas God has a special relationship with and concern for Israel (i. e. God has made certain promises to Israel that he must be true to), God is no respecter of the pagans. God establishes and extinguishes the pagan nations as he sees fit, often on Israel's behalf.
Would it therefore be better to read God's final words in Jonah as a statement rather than as a question? Under this reading, God would vindicate Jonah's concern for justice, affirming that he will indeed destroy Nineveh (cf. Nahum), and neither the city's size nor its ignorance will restrain his wrath.