Why do people think I'm stupid because I told someone not to post their questions anymore?

She was saying that all the past killings by Christian peoples were justified. She said they did it in the name of Jesus and if President Obama were to do the same then he should have the right to do so. I told her no! I told her that the bible says we should love our fellow man. We shouldn't kill people and hurt others. I told her it's in the freakin 10 commandments! She was about to post this question when I stopped her and told her that she is just giving more fuel to people to throw on the fire. She's mad and me and told me I was stupid. Her family is mad at me and a couple of my friends said it wasn't a smart move. What's your opinion?