A question for Atheists

In reference to my lost post, Atheists responded by saying:

"Ray, you're just lying. There is no way you could be stupid enough to believe what you wrote. You're a liar, and the lies you are telling should be transparently obvious even to your flock."
"Bearing false witness is a full time job for you. How do you get anything else done?"
"Liar."
"You know that you're lying when you say that Dr. Dawkins believes in aliens."
"Stop lying."
"You are lying, Mr. Comfort."
"Sorry Ray but there is no way what so ever that this latest post of yours can be taken as anything but outright lying on your part."
"He either knows nothing about the topic he's preaching on, or he's lying."
"As you are known to be a serial liar, it is likely that you are aware of that fact, but that you are lying regardless."

Could someone explain to me why an Atheist thinks it’s wrong to lie? It’s not against the law, so what’s the problem? Is there another Law I should know about?

If you think lying is wrong, who says so? You? What if I say that lying is right? If you don’t think it’s morally wrong to lie, why then do you accuse me of lying, as though I had done something wrong?