He should be thought it's evil.
Is that "he should be thought of as evil", or "he should have thought about it, and known that it's evil"? They're very different phrases, and your sentence structure makes no sense.
Good and evil are like whilte and black. There's no grey zone.
Where do you live, Setharmon? I want to live in your Utopia of Black and White, too!
Is a murder justified when the murdered man is evil? Is it justified when the murderer did it within a noble cause? What about the murdered man's relatives? Is lying considered evil? Sloth? Gluttony? Pride? Doesn't that make every single person on Earth evil? (Because you aren't going to find a person who's never lied in his/her life.) At which point do you start calling a person evil?
Oh, and look at children. Bullies who beat smaller kids up. Kids who torture domestic pets. Are they evil, too? Is this black and white?
Besides really everyone has a sence of good and evil.
Really? What about newborn babies? I didn't know that babies were born with an ingrained sense of good and evil pre-programmed into their brains. IMO, it's all about upbringing and society.