I'm not going to generalize here. What I'm saying is simply from personal experiences. I know I haven't met every atheists out there. Quite a few atheists have, over the past few years, grown considerably hostile towards religion. I believe this is due to a variety of situations. The first and foremost is that some(particularly the anti-theists) have experienced a negative situation either from a religious person/religious ideology, or have experienced a negative situation while claiming religion. From my experience, there are some atheists that are bitter simply because that, while they were religious, something terrible happened. Whether it was a close family member dying or a loss of property, they experienced a negative instance all while trusting in what they, at the time, believed to be a loving, caring deity. So, they feeling of betrayal leads then to become angry to the point of hateful at religion. Another reason is the violence and extremism caused by religion today. Whether you are close to a terrorist event or not, you feel the impact. And when religion is the cause of such attacks, it only fuels more hatred, fear, and disapproval of religion. And humans seem to always want to generalize, so naturally, religious people get generalized like everything else. Yet another reason is the fact that some views of religion are viewed as "freedom-suppressing". As time has gone on, people have become more obsessed with this notion of "freedom". It of course goes through the cycle of what's popular at the time being the right of the people, while the unpopular opinion/action is eventually strictly limited or outlawed. And of course, as coincidence would have it, many of the countries obsessed with the ideology of freedom, are majority religious(and more specifically Christian), and thus, majority scrutinized(and again, since Christianity is the largest, it's going to be more scrutinized). Obviously, not all atheist are like this. And really, if you should remember anything, OP, it's that internet atheists =/= real atheists. Many internet atheists are just edgy teens with nothing better to do than argue for fuсk's sake. While some are merely translating their actual though process, others are only going a little extreme because they feel powerful behind a screen. Powerful enough to insult intelligence and beliefs.