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.
As a reaction, I think its underlying impetus is islamophobic renaissance broughy to the forefront by 9/11 and the associated media and political response. Angloids latched on, in part, to Christianity because it was proximal, but in terms of the material changes that were happening, and what consent needed to br manufactured, it really revolved around the question of how to dehumanize muslims and make them deserving targets of violence.
Some of the new atheists were pretty explicit that islam was their primary enemy and doubler and tripled and quadrupled down on islamophobic rhetoric even as people stopped caring about atheist stuff. That crowd is the same one that also went down the misogynist path.