It's not the fact that they celebrated his death that is most important. It's the fact that the people celebrating have no coherent understanding of who he was. All they know is "Media told me Iran bad. Iran bad means Iranian dying is bad man dying. Funny meme death of people I don't see as human."
You can tell based on responses they haven't read even a single article in full about anything even tangentially related to the man.
I understand what an analogy is. But you know (and I know) that we don't make analogies at random. There's a specific reason you chose Bin Laden and Hitler to make the analogy. Even comparing Bin Laden and Hitler is dishonest and lacks appropriate context.
I'd say Raisi's death celebration is more akin to celebrating the death of someone like Omar Torrijos (Panama), and I'm not speaking of similarity of death itself or the conditons that created the death. I'm talking about their respective policies.
Death happens everyday and you chose to make the specific comparisons you did. It wasn't an accident, no one forced it into your brain. You did that.