Anime and nerd fans often call Light Yagami “evil” because of his lies, manipulation, and gaslighting, but rarely apply that same criticism to superheroes—especially Superman. Clark Kent does the same things Light does, just less skillfully. Maintaining a secret identity means constantly lying and manipulating people. Superman justifies it by claiming moral superiority, but if his son Jonathan were a superhero who lied and manipulated his parents the same way Light Yagami does Clark would be furious—even though he’s guilty of the same thing.
You’re making conclusions based on “good/bad” or “evil/just”. This means there are moral or philosophical definitions.
Light Yagami lies and manipulates people to get away with killing people. Clark Kent lies and possibly manipulates people to save or protect people.
Kant, I think, might say you’re wrong because as long as each of these people is doing what is true to themselves in their own moral code, they are equally “good”.
Bentham, I think, would say you’re wrong these are not the same because the outcome from Light’s actions is mass murder, while the outcome of Clark’s actions is safety, peace, and protection.