In a nutshell, the calvinist pretty much believes the vast majority of humanity is evil and damned to Hell, that God wants it that way and is pleased by their damnation. So the verse "God so loved the world" becomes kind of a pseudo love, a love that God has already made for the vast mojority, impossible to respond to. To wit, God created millions and millions of people to provide the backdrop of darkness for his diamonds of redemption to shine, their damnation causes his objects of mercy to shine more brightly, to appreciate His "love" more deeply.
Hmm, sounds a lot like Fred Phelps to me!