Disney's Hercules, Clash of the Titans, and this...
In the original Greek myths, Hades was a fairly stand up guy. Yes, he ruled over the Greek equivalent of Hell, but he also handled the Greek equivalents of Heaven, Purgatory, the Pearly Gates, etc. Persephone's main complaint about being his wife was not that he was cruel- he lavished her with all the luxury he could afford, and he was the richest of the gods- but because he was her father's older brother, and thus considerably older than her.
Greek myth is full of awesomely evil monstrous beings, from Titans to the offspring of Typhon and Echidna, to those cursed by gods (of which, Hades was responsible for far less than many of his brethren... Athena, who's almost always portrayed as kind and generous, turned a woman into a spider for BEING A BETTER WEAVER for crying out loud). Why do modern storytellers think Hades makes such a great villain?
Mostly the responses to this post focused on what Persephone's real grievances were with Hades, which for me is far less interesting than the actual question posed, (especially because I don't believe Persephone actually had grievances with Hades. Standard Homer aside, I think she was not quite "all unwilling".)
In my opinion, the reason we see mainstream media vilifying Hades is that it is difficult for a mind steeped in Christian mythos to accept the ruler of "Hell" as anyone other than Satan himself. In this system of thinking, Hades being portrayed as he actually is would probably cause an outrage. Hades is the judge of souls for both good and ill and Persephone is the intermediary--the two together representing justice tempered with mercy--the exact dynamic between Christ and "God the Father".
And how dare we, even in the interest of accuracy, compare these Pagan deities so directly to the Christian ones? How dare we imply that the Christian mythos is not entirely original?
When a story dares to honor the Gods by educating a new generation about them, I think it is acceptable to make a few concessions like this to avoid the project being quashed before it ever sees the light of day. The real trick is making it provocatively accurate enough to inspire people to investigate the myth behind the myth and, hopefully, the deeply moving spirituality behind it all.