Sinclair Ferguson talks about the moral issue of unblief.
Somewhere along the line it will become clear that the atheism that (atheists) claim is simple intellectual honesty in fact has deep moral roots because deep down, as Paul says in Romans 1:30, they are haters of God. Don’t you sometimes think to yourself, “Why do so many of these people who tell me they don’t believe in God get so angry about Him? After all, they’ve just told me that He doesn’t exist.”