Where does it say that he "does not pick out certain people beforehand"? Is this, like John 3:16, another one where you suppose that "whosever believes" is an open matter to God? The Greek gives no sense of the unknown, but merely means, "those that believe".
But besides that, all verses/ passages in the Bible are in the context of all the rest of it. You can't use one verse to cancel out the others that show he is particular in the extreme, and was so from the beginning. For him to elect is to CAUSE. And chance can cause nothing.