Spurgeon, like many Calvinists must have been unfamiliar with Jeremiah chapter 18, which Paul referred to in Romans 9:
Jer 18:1 The word which came to Jeremiah from the LORD, saying,
2 Arise, and go down to the potter's house, and there I will cause thee to hear my words.
3 Then I went down to the potter's house, and, behold, he wrought a work on the wheels.
4 And the vessel that he made of clay was marred in the hand of the potter: so he made it again another vessel, as seemed good to the potter to make it.
5 Then the word of the LORD came to me, saying,
6 O house of Israel, cannot I do with you as this potter? saith the LORD. Behold, as the clay is in the potter's hand, so are ye in mine hand, O house of Israel.
7 At what instant I shall speak concerning a nation, and concerning a kingdom, to pluck up, and to pull down, and to destroy it;
8 If that nation, against whom I have pronounced, turn from their evil, I will repent of the evil that I thought to do unto them.
9 And at what instant I shall speak concerning a nation, and concerning a kingdom, to build and to plant it;
10 If it do evil in my sight, that it obey not my voice, then I will repent of the good, wherewith I said I would benefit them.
11 Now therefore go to, speak to the men of Judah, and to the inhabitants of Jerusalem, saying, Thus saith the LORD; Behold, I frame evil against you, and devise a device against you: return ye now every one from his evil way, and make your ways and your doings good.
God was speaking of nations when he spoke of Jacob and Esau, and it is true that he loved Jacob and hated Esau, but there is nothing unconditional or unjust about it. God says in Jeremiah 18 (which Paul is referring to) that if he has spoken concerning a nation to pluck it up and destroy it, if that nation turns from it's evil, God will turn from the evil that he thought to do unto them. Likewise, God said that if he had spoken to build and plant a nation, if that nation do evil and not obey his voice, he would repent of the good that he said he would benefit them.
So, there is nothing unconditional in this, and there is nothing unjust in this, God will bless a nation that repents from their evil and does good, and God will punish a nation that turns from him and does evil.
Calvinists err because they do not know (or choose to ignore) OT scripture well.