I discussed this with Leighton, the false teacher who is drawing away disciples after himself while speaking twisted perverse things and he deemed it unfair. That's the foundational reason for their teaching; God is unfair, hence Romans 9:19-21 is on display in them.
As usual you take verses out of context
Paul interlocutor is a hardened Jew
who though elected for a noble purpose because of unfaithfulness was used to crucify the messiah
read Jer 18
Jeremiah 18:1-12 (KJV)
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.
12 And they said, There is no hope: but we will walk after our own devices, and we will every one do the imagination of his evil heart.
It concerns Israel
Israel for the most part was cutoff because of their own unbelief
Romans 9:30-32 (KJV)
30 What shall we say then? That the Gentiles, which followed not after righteousness, have attained to righteousness, even the righteousness which is of faith.
31 But Israel, which followed after the law of righteousness, hath not attained to the law of righteousness.
32 Wherefore? Because
they sought it not by faith, but as it were by the works of the law. For they stumbled at that stumblingstone;
Romans 11:19-23 (KJV)
19 Thou wilt say then, The branches were broken off, that I might be graffed in.
20 Well; because of unbelief they were broken off, and thou standest by faith. Be not highminded, but fear:
21 For if God spared not the natural branches,
take heed lest he also spare not thee.
22 Behold therefore the goodness and severity of God: on them which fell, severity; but toward thee, goodness, if thou continue in
his goodness: otherwise thou also shalt be cut off.
23 And they also, if they abide not still in unbelief, shall be graffed in: for God is able to graff them in again.
BTW there is no provisionist teaching God is unfair