I'm an atheist, I've been an atheist for 40 years, I've never hidden it, and I've gotten along just fine with a lot of theists and rarely had any problems with them over differences in worldviews. That's been my meat-world experience. My cyber-experience of contact between atheists and theists could not be more starkly different. It has been mostly them fighting and being very rude to each other, and conversations on religious topics are constantly interrupted by verbal abuse from people on either side -- if, that is, there was anything resembling an attempt at discussion to begin with. I don't know what this means. Some possible explanations:
1) I may have been fortunate in the people I've met face-to-face over the course of my life.
2) I may have been unfortunate in the people I've met online over the course of the past 5 years who argue about religion.
3) The people I've met face-to-face and those I've met online may be very similar people, who behave very differently depending upon whether they're interacting face-to-face or in cyberspace.
I was raised by liberal Christians. There was never the slightest hint of my parents disowning me or wanting nothing more to do with me, because I was openly atheistic. A lot of the atheists I've met online were raised by fundamentalist Christians, and they have been disowned and shunned by their families. Over and over again this turns out to be the background of people supporting irreligious billboards and trying to have the 10 Commandments removed from public buildings, and other atheist efforts which I tend to find useless or worse. And these are the same atheists I see behaving very rudely online toward theists -- Christians, mostly -- who are behaving very rudely toward them. (Cousins, feudin' and fightin'?)
So it may just be that the people meet face to face are not those I meet online.
It may be that atheists who come from liberal backgrounds like mine are either hanging out in different places online than I am, or that they are not as vocal as I am about being atheists, or both.
Or it may be that many people's manners are much worse online than offline. Maybe the very same people I meet face-to-face, who seem to take my atheism so calmly in stride, are actually very upset with it, but hide their dismay from me, and take it to the Internet, where they unload in the manner I'm accustomed to seeing online.
Whatever the reasons, the contrast between the behavior I see offline and that I see online is very striking. Perhaps it's very autistic of me to find the difference striking, while the neurologically-typical see nothing strange about people behaving very differently in the 2 spheres.