You are a 'Think Tank' member. So THINK.
If you want to insult an atheist, certainly religion is out, correct ? So if you want to insult an atheist, you would insult his family, his method of birth, his country of allegiance, how ugly he is, how fat he is, and so on.
But what would you get in return ? If he knows you are a Muslim, he would insult your Prophet. He is not going to think that since you insult his wife, he must insult your wife. This is the absurd line of your argument: 'Flag vs flag,religion vs religion'.
Nobody is going to be that stupid. If I am in a war, if I shot an enemy soldier in the leg, he is not going to shoot me in the leg but he will try to shoot me in the head or chest in order to assure a kill. Likewise, if an atheist is going to insult you, he is going to insult a religionist at the most emotionally significant item available: religion.
'Flag vs flag,religion vs religion' => that is a stupid argument for someone who is supposed to be in a 'Think Tank'.