The Gospel call is available to all who hear it, but not all are responsive to it. Only those who are drawn by the Father will submit to Christ? Jesus makes this clear in John 6. You are right in that salvation is available to both Jew and Gentile. We don't deny that. The Gospel will not be accepted by every single person, because the carnal mind cannot understand the things of God. It requires a new heart of flesh to replace the heart of stone and it requires effectual grace and faith given only by God. This isn't something we can muster up ourselves. The idolatry comes from those who make the claim it is "unfair" or "unjust" if God doesn't give everyone the same chance to be saved and that him choosing some and not others is "unfair". So people give him human attributes and decide for him what is fair and just. Not everyone is even given the Gospel call. Thousands, if not millions throughout history never heard the Gospel or were given a chance to be saved by it. Is that fair? Is that just? We don't want true justice from God, because that means all should be condemned and sentenced to hell. But God, in his grace, has chosen to save some, not for us, but for his own glory and purpose. It's not about us, it's about him. To claim the Gospel is not effectual for all but only those who obey muster up belief on their own is an attack on it's purpose. This is an attack on the finished work of Christ. Not all of mankind is redeemed or was meant to be redeemed. Jesus says he lays his life down for the sheep. His death on the cross was entirely effectual for those he died for. His name is Jesus because he will save his people from their sins. Those who are given to him by the Father will come to him. No one can come to him unless the Father draws them. This is what Jesus himself taught. He isn't hoping some will come to him and is disappointed when they don't. He already knows who are his. This is true from the Arminian perspective as well if you believe God knew all things before he even created all things. There is a set number of people who will be saved and a set number of people who won't. Those that are saved are those that were chosen to be, apart from any merit on their part.
You have warped it already. You claim obedience merits grace. This is contrary to scripture. The word of God is rejected because the world is condemned already. It takes intervention by God to save someone. The person who responds has done nothing themselves to make this happen. It was God who saved them. God who opened their eyes. God who raised them to spiritual life. God who gave them a heart of flesh. God who drew them. God who gifted them grace.