Definitions can be deceiving. Atheists that I grew up with were a variety of "not believing" or "unsure" of the existence of God, the latter of which you and I may identify as "agnostics". They were sincere and genuine.
When I say that they were "unsure" I mean that they were for the most part untroubled by their uncertainty, or at least as troubled as the person of faith is by their own path.
I think I understand these "atheists".
What we have today - parading as atheists and agnostics - are in reality "secular humanists". It's good to see that they are at least using the name "humanist, as they are in this article. Usually, they deliberately enjoy muddying up the waters by claiming to be atheists. I separate atheists from secular humanists based on their opposition to the concept of a deity. By the way, there are also secular humanists who put themselves forth as being Christians and Jews, as well. I have known a couple of these types - they use the pre-tense of being a person of faith to more strongly refute the position of a spiritual person.
I once got into it with a secular humanist pretending to be an agnostic when I referred to Buddhism as a world view or philosophy. She had a fit and told me that I could not classify a religion to suit my own purpose. She went on and on about it, while I pointed out that a true Buddhist would not be the least bit annoyed by how I referred to their philosophy,...or religion, nor would they expend an iota of energy refuting my position.
I get along fine with old school atheists. They challenge my faith and encourage me to look deeper. They make me slightly more conscious of the fact that I need to "walk the walk" as a reflection of my faith in Christ. Many of my Christian friends already know that I can not do this. We usually chuckle about this and urge and encourage each other on anyway.
Secular humanist, are easily identifiable by a profound bitterness. I have not met a single one that doesn't have a mean or spiteful streak in them. They are marked by their opposition to the concept of a God. I think this disposition stems from the fact that someone else has either laid claim or gotten credit for a position which they have chosen for themselves - "master of the Universe."
I know what you're referring to. Such people define themselves by their opposition to what they consider to be religion--and they oppose religion for ulterior motivers having nothing to do with the core issue.
Fortunately for me, I rarely actually have to deal with such people. And once they hear I'm an atheist, they leave me alone. One of the advantages of being an atheist, I guess :-)