Why is it that athiest often (not always) direct their argument for athiesism towards Christians? Why not direct your argument towards Buddists or Muslims or even New-agers? I mean they also believe in a higher power so why is it that only Christains seem to get knocked? Is it because your only point of reference is JWs and the bible and therefore easier to reference?
As already discussed, most atheists are from Christian cultures, so they coment on the religous group they know the most about.
Christians are also far more likely to engage in missionary work, which means they are putting their message 'out there' and getting paid back in kind.
Likewise, Christian beliefs are more likely to mould political beliefs or moral stances in the West than other religiosu beliefs, again making Christianity more of a target than religous groups who don't try and maake their beliefs the touch-stone of society.
See the reaction Muslims get when they try and get their beliefs heard in society, from both atheists and Christians, and you can understand why secular people object to Christian beliefs being used to try and restrict what they feel are freedoms.
Of course, having said this, those Christians causing atheistic reaction are not representative of all Christians.
An atheist's reaction to a "well, the Bible is allegorical and evolution is obviously true but I believe in the value of the message credited to Jesus and in some kind of higher power" Christian is vastly different to their reaction to their reaction to a "you are godless scum and will burn in hell, you have no right to your body or sexuality and god made everything in 6 x 24 hour days" Christian.