Calvinism doesn't need to be defended. It just needs to be clearly articulated, directly from the Bible, and whosoever has ears to hear will hear it.
There's no point to Calvinism if it can't be articulated from the Bible. There are numerous passages of scripture supporting the five points of Calvinism, and whoever has ears to hear, let them hear.
Calvinism is the teaching that God saves whoever He chooses (Romans 9:10-24), that even the most obstinate sinner can be transformed by God’s amazing grace (John 6:44). If you have a problem with that, you might have a problem with the Bible, and you might need to stop praying for God to save the lost.