God is concerned about all of His creation. We read in Amos 7 that the purpose of His wrath is to draw people to repentence. Even King Ahab who "did more to provoke the LORD, the God of Israel, to anger than all the kings of Israel who were before him." (1 Ki 16:33) found favor from God. After his wife Jezebel killed the prophets, he had Naboth kills so he could get his garden, and he did evil things over and over, we find God saying this:
Quite frankly I can understand why the prophets would throw up their hands. God can be very frustrating in His love and endurance. We would love for Him to strike people down but that isn't the way He works.
So, no, God does not feigns concern. His concern is real. The issue isn't God's love. It's that people don't care about God.
But your point is an interesting one. If someone went today to, say, Baltimore and told people they needed to repent and turn to God, how many do you think would put on sack cloth?
The problem we have today is that there is no fear of God because few believe in sin. We have preached God is love for so long that we have forgotten the message is to repent, call on the Lord and you will be saved. Instead, it's all about what God will give us.
My thoughts were that God sent Jonah while they were still sinning, and God says He did it because He was already concerned about them.
It seems to me that any appeal to foreknowledge or foreordination can be used to change God's simple expression of His concern by explaining it away.
We then must decide if God intended us to believe that really He didn't actually care for them.