But all the souls that it has are not evil. At least they didn't start out that way. Though I have my doubts about Horace Derwent. He may have been the one that cursed it. Or he's the demon that was summoned. The only way to find out is to meet him.
And I don't know if they did this in your timeline, or if it was for the Television series only, the hotel was supposed to be rebuilt. And if Horace stuck around, he could have restarted his collection.