Every unbeliever God has given grace to make them able to choose what they wish.
For the grace of God that brings salvation has appeared to all men, teaching us
that, denying ungodliness and worldly lusts, we should live soberly, righteously,
and godly in the present age." Titus 2:11-12
God's grace enables the recipient while the grace is being applied, to be able to choose as he really wants to choose.
That is why all unbelievers will be found to be without excuse.
If grace was denied the unbeliever?
They would have a legitimate reason to appeal the verdict.
TULIP Calvinism hit a wall with a mistake in understanding what the Bible speaks of.
Sad to say...
Those with a streak of self righteousness like what this mistake tells them.