When God says "thou shall not kill" and you kill millions of times, you are not Christian. Christians do not proclaim themselves to be replacements for God either.
Hitler was an antichrist.
Atheists are just annoying.
These are all from the bible, saying it's ok to murder people under the right circumstances:
"If a man lies with a male as with a women, both of them shall be put to death for their abominable deed; they have forfeited their lives." (Leviticus 20:13 NAB)
You should not let a sorceress live. (Exodus 22:17 NAB)
A man or a woman who acts as a medium or fortuneteller shall be put to death by stoning; they have no one but themselves to blame for their death. (Leviticus 20:27 NAB)
Whoever strikes his father or mother shall be put to death. (Exodus 21:15 NAB)
If a man commits adultery with another man's wife, both the man and the woman must be put to death. (Leviticus 20:10 NLT)
Whoever sacrifices to any god, except the Lord alone, shall be doomed. (Exodus 22:19 NAB)
They entered into a covenant to seek the Lord, the God of their fathers, with all their heart and soul; and everyone who would not seek the Lord, the God of Israel, was to be put to death, whether small or great, whether man or woman. (2 Chronicles 15:12-13 NAB)
Suppose you hear in one of the towns the LORD your God is giving you that some worthless rabble among you have led their fellow citizens astray by encouraging them to worship foreign gods. In such cases, you must examine the facts carefully. If you find it is true and can prove that such a detestable act has occurred among you, you must attack that town and completely destroy all its inhabitants, as well as all the livestock. Then you must pile all the plunder in the middle of the street and burn it. Put the entire town to the torch as a burnt offering to the LORD your God. That town must remain a ruin forever; it may never be rebuilt. Keep none of the plunder that has been set apart for destruction. Then the LORD will turn from his fierce anger and be merciful to you. He will have compassion on you and make you a great nation, just as he solemnly promised your ancestors. "The LORD your God will be merciful only if you obey him and keep all the commands I am giving you today, doing what is pleasing to him." (Deuteronomy 13:13-19 NLT)