[This is from my other blogs, but I figured I'd put it here too. Just to heavy things up a bit. It's my tiniest version of my "But predestination!" post. The short version with more memes and quotes and information can be found here, and the longest version (a series of posts full of many more Calvinist comments, my Calvinist ex-pastor's sermons, and my replies to them, written for my own amusement and for my ex-church) can be found by starting here. But this tiny version includes only the most basic parts you need to know, with a few memes and quotes thrown in to spice it up.]
At the heart of Calvinism is predestination and God's sovereignty (among other things, like "total depravity"), which according to Calvinism essentially amounts to: "God preplans and controls everything, even sin and evil and all our decisions, and so He pre-picks who goes to heaven and who goes to hell. He causes the 'elect' to believe in Him and be saved, but He made sure the 'non-elect' have no chance or ability to believe and be saved because He predetermined they'd go to hell (and so Jesus never died for them anyway), all for His glory."
And if we push back against this - if we say Jesus died for all people and God offers salvation to all people and that He lets us decide to accept or reject it - Calvinists go "But God is sovereign, and predestination is in the Bible, and so you have to believe it!"
But the problem is not that we misunderstand the Bible or can't accept biblical truth. It's that Calvinists mis-define both sovereignty and predestination (among other things).