The particular neckbeardy, fedora wearing, Sam Harris listening trend of atheism was a pretty clear reaction to the evangelical psychosis of the Bush administration.
Other geriatrics here can attest that the character of Christianity at the time was way different than it is now. These days, the fascists are more "culturally Christian" and avoid overt bible apologism. But back in the day, these people were constantly on TV spewing young earth creationism and other shit, and they were largely taken seriously. It's hard to believe now how much time was spent "debating" evolution back then. The atheist backlash at least affected discourse aesthetically for some time, making these views laughable, which deplatformed a lot of evangelicals or made them hide their power levels on TV.
Some argue that this brand of atheism justifies imperialism. It does so really only in theory. There really is no material basis for atheists in the US to justify an invasion anywhere in the world. The truth is that Christianity is still a far more powerful force for imperialism. Bush said that God told him to invade Iraq. I don't see any president saying anytime soon that the US needs to secularize a country through force.
If fundamentalist and political religiosity were defeated, then belligerent atheism would dissolve, but the reverse is not true.
Overall, it really does seem like people over emphasize this group of internet no-lifers because of the cultural cringe they manifested.
I think at heart, they're just people who greatly enjoy pissing on other people's treasured values. When Christianity was the norm, they pissed all over it with a great deal of glee. Now that the shine's come off Christianity and social justice values have made great strides into our lives, they piss all over that, too.
Atheism/what-have-you isn't a positive ideology, it's a negative one. It's not about what you should do, but what other people are doing wrong. And what's that saying about people being wrong on the internet?