I don't think it is
It isn't your life to take
if they really are evil and obviously always will be, then killing them is protecting society
Yes but it depends on what type of evil we're talking about here. Serial killer? Serial rapist? Killers? The person responsible for war crimes? Some of the evil people are redeemable, some aren't. I believe in the second chance, but I think it's moral cowardice to stand idle and let the evil running amok.
there are only three reason to take another's life: self-defense, defense of others, and in punishment severe enough. Evil people do not need to be kill because that person can change.
I'm a consequntalist. So if a person is contained and unable to do harm I'd say it's wrong to kill them. I belive everyone has something to contribute to society and everyone is useful in a way. Revenge is bad.
Let's first define murder. Murder is the killing of one individual by another individual without authorization or due cause such as in self defense or in defense of another person. Murder is against the law in virtually every place where law exists. Murder is wrong because it is the unsanctioned killing of another. Some nations and states have chosen never to kill any person within their own jurisdiction and they will also not extradite to nations who do. Other nations and states have established a death penalty for certain crimes according to their law. This type of sanctioned killing is closely regulated to ensure no one or as few as possible are killed unjustly. Taking the law into your own hands is both dangerous and illegal. Therefore all murder is wrong, whether the person you want to kill deserves to die or not.
No such thing as a "evil" person. Evil is what we label certain things people do so when people do that certain act it is "evil"