I read the article, and I more-or-less think it has merit. He's saying that people that identify as atheists falsely believe they are free of moral assumptions. His major points seem to be:
1. all atheists have at least some moral viewpoints that are rooted in biases and assumptions (because that's how humans work)
2. atheists are sometimes guilty of cherry-picking evidence to support their biased and assumption-ridden moral viewpoints
3. atheists that claim they used logic to come to their moral viewpoint when they are actually cherry-picking are just as false as theists that base their moral viewpoints on religion
But from a purely definitional perspective, I think he's wrong. Atheism is just a lack of belief in deities. You can be a scientist or woo-practitioner or believer of magic and be an atheist.