>>41310288 (OP)
I will offer a secular explanation: Some people are naturally zealous believers by nature, and wish to impose (as is common) their 'correct' understanding of the world upon everyone else, by force if necessary. Their specific beliefs are very variable, they can be Christian, Muslim, Atheist, Liberal, etc. But the same personality traits manifest through them. If they are sufficiently magnified, they may be unable to even tolerate someone not accepting 'the truth' being in a room with them. Converts Zeal is also a part of this, they were blind, but now they see the truth! And they will abide by that truth and tirelessly fight for it! Just that in this case the conversion was out of religion, rather than into one. Extremely principled people that think religion is inherently evil also qualify.
The second important type of extreme religion hater is what I would call a The Victim. You allude to them with your comment about Vicarial molestation, though it usually is not that bad. Usually it is people who were hurt by abusive religious parents, exploited by churches, members of cults, disowned for being Gay, ostracized, etc. They draw from their experience that organized religion and their concepts of God are harmful and evil; they wish to eradicate them.
Btw, it's nether here nor there but the explanations from Christians ITT strike me as self masturbatory reaffirmations of belief rather than an actual attempt at understanding the phenomenon. Plus they use that sanctimonious catholic U.S think-tank tone and that grates me.
P.S: I hate 'New Atheism' so much. It duped like three generations of religious people into thinking 'Atheism' is a belief system like Christianity is.