Are you suggesting that Talk Origion quotes people they do not agree with? You mean that atheists do not even agree with themselves? That would make you all a lot of loners.
Sometimes people quote those they disagree with to refute them. I am suggesting you have not provided the context needed for me to evaluate Talk Origins' use of the statement.
In fact, not all atheists are perfectly alike or believe the exact same things. For example, my friends and I disagree about which song is the Best Song Ever. I usually don't feel lonely, though, because I'm having fun sharing music with them.
Atheists share a lack of belief in God. they need not share anything else (by the way, I don't know Popper that well, he may not be an atheist. In fact, Talk Origins, which is a place I'm not familiar with, may not even be an atheist website, but only one that promotes evolutionary theory. )
Anyways, atheists can and do interact in almost every possible way, which would include disagreement. It would also include agreement, friendship, love and marriage. See, atheists are people, like you and me. They are diverse, as people tend to be. Some like hip-hop, and some like classical. That's okay. We can still get along with each other and with theists.
For example, some atheists couldn't care less about other people. Some of us, by way of contrast, spend 10-12 hours a day working for barely any money at non-profits dedicated to education, community service, and social justice because we like people and want to spend that much time each day working with them. Some of us spend the vast majority of our lives helping the poor, downtrodden, oppressed, sick, and neglected not just because Jesus told us to (though we think he was a cool dude), but because it's the right thing to do. Not to mention unbelievably rewarding.
But, of course, what am I thinking? You know more about millions and millions of people (including me) than they do, and you know that because we disagree with each other about some things atheists are loners. None of us would dream of spending 10-12 hours a day doing nothing but interacting with and helping people. We certainly wouldn't be helping people who have religious, philosophical, and political beliefs we disagree with , despite the fact that every person has something to offer this world, and is worthy of our deepest respect and love. None of us could possibly believe so deeply in the potential and worth of others.
There wouldn't be enough atheists out there, and they wouldn't be diverse enough, that some of them could be quite social. Unlike Christians, there is not one of us capable of having both the genes and upbringing that would allow him or her to like people to the extent that he or she will resist a strong societal call to do nothing but make money and focus on themselves, their families, and their friends to the exclusion of every other member of society.
Furthermore, there is nothing more to us than our atheism. There is no way that there could be other parts of our lives, and other foundations to build relationships with other people on, such as a love of music, service, math, science,children, history, sports, computers, or family.
No, you're right. We're all loners. Every single one of us. My life is a lie.
Or maybe we're people just like Christians are, and that making vague, generalized statements about atheists is about as smart as making vague, generalized statements about Christians.
edit: Just after I posted this, I finished a satisfying math problem, and at that moment one of Miles Davis' masterpieces (Blue in Green) from his masterpiece album Kind of Blue started coming out of my speakers. Right now I think I'm going to, in my typical loner atheist style, share both of these joys with my best friend.