How many people have had the experience of having to deal with an AYA (Angry Young Atheist). The AYA doesn't see any need for politeness or courtesy: he goes on the attack right away. He (or she) is new to atheism, so they have this almost evangelical tone. They love going to christian chats and letting loose.
They haven't been in the trenches long enough to realize that not only does the direct attack approach not work, it actually alienates their audience.
I admit I was an AYA at one time. Then I realized that wasn't working. Politeness is never wasted.