At last a sensible question! Thank you! 'Everyone who calls on the name of the Lord shall be saved.' That's in the Bible and therefore non-negotiable.
But men and women will not call on the name of the Lord. John 3:19. 'And this is the condemnation; that the light has come into the world, and men loved darkness rather than light, because their deeds were evil.' Romans 3:11. 'There is none who seeks after God.' 1 Cor. 2:14. 'But the natural man does not receive the things of the Spirit of God.....' Jer. 13:23. 'Can the Ethiopean change his skin, or the leopard his spots? Then may you also do good who are accustomed to doing evil.'
The non-elect cannot call upon the Lord, not because He prevents them, but because they have wicked, unbelieving hearts. Therefore God, in His great mercy, has chosen a great crowd of men and women, from every nation, tribe, people and tongue, for salvation, and has opened their hearts to receive the Gospel of Jesus Christ. Titus 3:3-7. For we ourselves [Paul and Titus] were also once foolish, disobedient, deceived, serving various lusts amd pleasures, living in malice and envy, hateful and hating one another. But when the kindness of God our Saviour towards man appeared, not by works of righteousness that we have done, but according to His mercy He saved us, through the washing of regeneration and renewing of the Holy Spirit, whom He poured out on us abundantly through Jesus Christ our Saviour, that having been justified by His grace we should become heirs according to the hope of eternal life.' [see also Ephesians 2:1-10]
Through God's mercy and the new birth, men and women who, of their own free will, rejected God, now, of their own free will, renewed by the Holy Spirit, trust in Him and receive salvation.
Very quickly, hyper-Clavinists believe that the Gospel should not be preached to all, but only to "sensible sinners." Well, if they were sensible they wouldn't be sinners! Calvinists, including Calvin himself and A.W. Pink, believe that the Gospel should be preached freely to all, and sinners tols that if they will repent and trust in Christ, they will be saved.