I have been an atheist since 1973 and do not remember at any time did I associate atheism with either humanism or social activism. But I have always been involved in some of social activism. However, in fairness, until recently the idea of openly discussing atheism publicly was unheard of. Social pressure often made doing do either uncomfortable or replete with negative social consequences.

I think that a lot of the identification may be a result of recent responses to many of the actions being perpetuated by many of the dominant Christian hypocrites

I see, from the people I surround myself with, that atheists are more likely to DO things to help and be more active in the community. Where as, in my experience, theists are more likely to pray versus actually doing anything to help.

I have been saying for years, atheists aren't less caring or giving, they just don't go looking for recognition for their acts. But, with social media and the internet, religious organizations have been so "in your face" about their charities, touting that only good "god fearing" people are so willing to give, that atheists have been pushed to speak out about the good they do for others. Basically most religious charity's are attention whores.

I suspect it is simply because those drawn to atheism, humanism or social activism are more likely to be thinkers. We just contemplate more.

The fact is ...that many religious share many many Humanist values, if you subtract the religious dogma, and removethe belief in any god..you may well end up with a Humanist.

All I ever get compared with is the devil and accused of eating babies.

I believe in a variety of definitions about Humanism (these excerpts are available with their entire text at the AHA website [americanhumanist.org] :
"Humanism is a progressive lifestance that, without theism or other supernatural beliefs, affirms our ability and responsibility to lead meaningful, ethical lives capable of adding to the greater good of humanity."

"Humanism is a rational philosophy informed by science, inspired by art, and motivated by compassion. Affirming the dignity of each human being, it supports the maximization of individual liberty and opportunity consonant with social and planetary responsibility. It advocates the extension of participatory democracy and the expansion of the open society, standing for human rights and social justice."

"Humanism is a democratic and ethical lifestance which affirms that human beings have the right and responsibility to give meaning and shape to their own lives. It stands for the building of a more humane society through an ethics based on human and other natural values in a spirit of reason and free inquiry through human capabilities."

"....Humanists believe that this is the only life of which we have certain knowledge and that we owe it to ourselves and others to make it the best life possible for ourselves and all with whom we share this fragile planet. A belief that when people are free to think for themselves, using reason and knowledge as their tools, they are best able to solve this world’s problems. "

"...Humanism serves, for many humanists, some of the psychological and social functions of a religion, but without belief in deities, transcendental entities, miracles, life after death, and the supernatural... Humanists stand for the building of a more humane, just, compassionate, and democratic society using a pragmatic ethics based on human reason, experience, and reliable knowledge-an ethics that judges the consequences of human actions by the well-being of all life on Earth...."

"...Humanism’s focus, then, is on using human efforts to meet human needs and wants in this world. History shows that those efforts are most effective when they involve both compassion and the scientific method – which includes reliance on reason, evidence, and free inquiry. Humanism says people can find purpose in life and maximize their long-term happiness by developing their talents and using those talents for the service of humanity.... While service to others is a major focus of Humanism, recreation and relaxation are not ignored, for these too are necessary for long-term health and happiness. The key is moderation in all things.... "

It is about as synonymous as religion with moral values. It has nothing to do with a demographic, culture or belief.

It’s not synonymous with humanism.

I put it like this..

Unrestrained critical-thinking leads to atheism; unrestrained compassion leads to humanism. They often go together.

I wasn't aware that it did. Is there a study on this? I do think that because of the fact that agnostics and atheists think outside of the narrow box that has been in place in religion we are much more prone to have a wider range of ideas and possibilities that would not be feasible by Christian thinkers.