How does the absence of a god lead to all humans being equal? How does the absence of a god make homosexuals equal to hetrosexuals? For the record, I believe in these things, but I do not derive them from the notion that there is no god.
Sure, religion in general lashes out at the idea that homosexuals are equal, but removing that religious belief leaves you in a neutral place. You can't use the absence of god to prove that all people are equal.
In fact, by the absence of a creator and his divine mandate of equality, we are left with a very materialistic view, and the facts speak for themselves. Not all people are equal. Some people are slower than me, some people are stronger than me, but there are even people who are weaker, slower, and less intelligent than me. There are people who are my lesser in every single aspect, and people who are my superior in every aspect.
The absence of god does not mean an adherence to science. One can perfectly argue against science without invoking god, perhaps even more extreme than some religious could even contemplate.
A political belief can't just be a random collection of positions. If a political movement has no internal logic, no foundation of philosophy, it will wither and die.
Let us make the comparison to math. Math is not about giving the correct answer, it is about being able to deduce the correct answer when presented with an equation. If a child understands the basic concept of 1+1, he will know the answer to 1+2. You do not need to teach every possible combination, you need to teach the underlying principle.
Political systems are the same in that they need to be grounded in something more than positions. A communist needs to understand that, when faced with a new problem, he can give a communist answer. He doesn't need to be told every single answer to every single problem, he needs to understand the core, and elaborate from that center.
Atheists share a lot of beliefs, but it can't be used as the foundation for a political belief, it lacks philosophical grounding, and the more you try to fix that problem, the more you realize that the atheist-aspect becomes trivial.
This Atheism+ has no political heart, no core. It is just a mash-up of what most atheists believe.
Humanism gives most atheists their outlook on life, not the lack of a god. The position of man is more important in a world without gods.
This, in all honesty, seems to be hijacking atheism.