Descendants Theory: Why Hades hates Auradon

So, I know it's been a while since I've released a proper theory but I have had a thought. 

In all trailers so far, Hades has expressed his hatred towards Auradon, King Adam and Queen Belle. He hasn't so far mentioned Hercules and Meg, his original enemies. He says he doesn't belong on the Isle, something that other villains haven't expressed yet.

MY THEORY

I think of what happened to Hades after his movie Hercules. He isn't mortal, so he can't really die. My guess is that he keeps on ruling the Underworld, and the place of the dead. This job wasn't one he chose, but his brother Zeus gave it to him, so it was a punishment in itself, always ruling souls of the departed.

When Adam and Belle started Auradon, they brought back certain villains (Maleficent, Ursula, Evil Queen, Jafar, Gaston etc.) from the dead. How did they do this?

The only way I think they were able to do this is with Hades's help. They made a deal with him, like Megara and Hercules did. Belle and Adam promised not to further punish him if he'd tell them how to bring back villains from the dead, getting their souls from the River of Lost Souls (Styx). 
BUT, Belle and Adam broke their promise and locked up Hades as well on the Isle, because they didn't trust him. 

For the next four years, Hades teamed up with Maleficent to plan and plot revenge on all heroes. He told her about the power of Fairy Godmother but Maleficent started fearing Hades. When she got pregnant, she knew that both she and her daughter were mortal and after their deaths, they would be servants to Hades forever, while he ruled the dead and the living. She couldn't bear the thought and so she locked him up in a underground cave on the Isle and lied to Mal about her father.

Now in Descendants 3, Hades knows he can't kill the Auradon citizens, as Zeus would just bring them back to life. And so, he simply turns the VK's into stone statues.