Here's one of many reasons I don't think Calvinism is consistent with the Bible. I think most people would agree that God is far greater than human beings. Anything you can do, God can do better. God can do anything better than you. The obvious exception is sin, however the fact that God cannot even be tempted to sin is also a result of the fact that God is better than you.
Now, the Bible says that God is love (1 John 4:8). If you do not know love, it is said that you don't know God. Love is such a powerful attribute of God that He is actually willing to tell us, through His Apostle, that He is love. If God is greater than us at everything, and His greatest attribute is love, it logically follows that He will always be more loving than we are. I don't think a Calvinist would deny this, and I dread the day I have the misfortune of being proven wrong.
Just as God is love, we who are made in His image should also be love. We are made in the image of God, God is love, therefore we are made in the image of love. As such, God has given us a number of commands relating to love, chief among which are "You shall love the Lord your God with all your heart, with all your soul, and with all your mind" and "you shall love your neighbour as yourself" (Matthew 22:36-40).
But it doesn't stop there, because God actually tells us to love our enemies (Matthew 5:43-44). He even follows it up with "that you may be sons of your Father in heaven; for He makes His sun rise on the evil and on the good, and sends rain on the just and on the unjust. For if you love those who love you, what reward have you? Do not even the tax collectors do the same? And if you greet your brethren only, what do you do more than others? Do not even the tax collectors do so? Therefore you shall be perfect, just as your Father in heaven is perfect." (v45-48)
So, God commands us to love our enemies. Now, if God commands us to love His enemies, does it not follow that therefore, God loves His enemies? Of course. Not only does it logically follow, it is explicitly described in the passage! If we love our enemies, then we will be perfect, just as our Father in Heaven is perfect. The two are directly equivalent: We attain perfection by loving our enemies as our Father loves His enemies.
And how does God love His enemies? Well, according to the passage in question, it is by causing rain to fall on the just and the unjust, but in Romans 5:8-10, we are told that God demonstrates His love for us, who were previously His enemies, by reconciling us to Himself by the blood of His own Son. Thus, if we are to love our enemies, even those who are not our brethren, and the cross is how God shows His love for His enemies, it just seems impossible that God would not also demonstrate His love to those enemies who refuse that love by means of the cross.
God is infinitely greater than we will ever be, and so if God gives us a command, you can be certain He is better at it than we ever could be. God is just, and so there will be a time when His wrath befalls those who insist on resisting His salvation, but this by no means indicates that He did not offer it to them. Salvation is by grace, through faith, not by being God's favourite.