I don't think its anything deep rooted. If someone said they believed that fairies were living in their bathroom and said they spoke to them daily then they would de deemed as deluded. However if someone says they speak to a god daily then they are just a christian. I don't see why one should be given special status over the other. Its not deep rooted anger or self defence. Its just dismissal of the absurd. That's pretty much how Everyone I know regards religion.
The bold part confirms what Hizikyah was saying: that modern atheists are very shallow and ignorant in respect of what christianity is. For instance, for almost all atheists God is easily replaceable (in their arguments and examples) with Santa Clause, Bigfoot, Tooth-fairy etc.
At first I thought atheists do this out of mockery and disrespect. But this clichee about Santa Clause keeps on coming over and over and I begin to suspect that most atheists do actually put God on the same ontologic level with Santa Clause. As if the existence or non-existence of Santa Clause, Bigfoot, Tooth-fairy, Spiderman etc. would have the exact same impact on human life (and meaning of life), on cosmos (and its purpose) etc. as the existence or non-existence of God.