Iran is retaliating because Israel attacked bombed their embassy and killed one of their generals. This was guaranteed to happen as soon as they did that.
Iran has publicly stated they have no intention of any other attacks. So there is no reason whatsoever to jump to conclusions that Iran is trying to destroy Israel. You can’t think about countries as cartoon villains.
We can debate if Israel was justified in their initial attack. But you can’t ignore that Israel deliberately attacked Iran’s embassy. And it was entirely expected that Iran would attack back.
If you don’t like people jumping to the conclusion that Israel wanted to destroy Palestine, then you can’t jump to the same conclusion with Iran.