Foreign enemies are more interesting to me as they are truly complex and look deeper into human nature as they are driven by far more compelling reasons. The inner enemies are meanwhile more pseudocomplex as you try to understand them and as they suggest that there is an option for peace.It is the reason why their ideological foundation is so weak and why Pain ultimately collapses.
Look for example, how Madara becomes. These characters are all laughably naive and childish in their world views. One might even wonder if they are even alive. Now, a proponent of Realpolitik, Asami would inevitably come to despise them.
Naruto’s antagonists shouldn’t be the gold standard because their ideologies collapse on their own. They identify real problems, but their solutions rely on fear, control, or illusion, which makes them morally and practically unconvincing. Great antagonists challenge the hero with a viable alternative — not a self-defeating one.
That's why Pain is so painful yet. Its philosophy about the cycle of hatred, the legacy of sin, and wounds is truly real.