Why would you assume that we would take any offense with that text.... God has compassion on whom He wants, when He wants, for whatever reason He wants.....In Calvinism - that text should not exist.
God does state that very thing over and over in scripture....... with the exception, at least I cannot recall, God saying He does not need a reason. His reasons are sufficient. He does not have to reveal His reasons to us.In Calvinism God SHOULD say "I am God, I am sovereign I can do what I want and don't actually need a reason.
Who has a right to challange God? Who has God authorized to challange Him?In fact I deny you (Jonah) the right to challenge me".
If you are saying that.......That would be "calvinism".
(1) God having the right to do as He will among the armies of heaven and the inhabitants of earth.
(2) And that our having no right to challange what He has proclaimed or ordained.
(3) And that His reason for doing whatever it is He decides to do is His own and sufficient....
.........would be Calvinism.
Then I would say you are beginning to have a grasp of some of the things we draw from scripture to proclaim....