What evidance do we have in Ramayana about Ravana's Evil?

This podcast detail a conversation analyzing the Ramayana,challenging the traditional portrayal of Rama as a hero and Ravana as a villain. A user, Pasan, argues that Rama's actions are morally reprehensible, while Ravana, despite his flaws, acted justifiably. Pasan further proposes a theory connecting Ravana's downfall to a possible ancient technological catastrophe, potentially a nuclear event, and suggests that Ravana may be a misunderstood Vishnu avatar.