I don't care that much about other people's beliefs as long as they don't interfere with my life. However, I care very much about humankind and our planet. I don't have any biological offspring, but there are children whose future I care deeply about, and to be honest, I hope I don't live to see the destruction of the species and the earth that seems to be inevitable.
I don't proselytize because I'm not good at it, but if I could do it successfully, I would.
I think others' beliefs are important because the religions that dominate the world are inherently anti-science. People have come to believe that faith is more important than knowledge, and the powerful manipulate them based on that belief. As long as that attitude prevails, we will continue accelerating toward the precipice.

My atheism rarely impacts on my social life even though I live in the hotspot of Northern Ireland .
I don't continuosuly put my athieism at the forefront of my life it is absolutely of no consequence to me. Maybe if I had been religious and had a struggle to give it up it would have been different but theism has never been part of my life . When I first came here I was baffled by people asking my partner three questions - (You only need three to find out if someone is protestant or catholic) - No one was in the least bothered to ask me the three questions because I was English and so didn't count .I don't have a belief so church dogma cannot touch me and I certainly would nt proseletyse atheism what would that give me? I believe in nothing except death and taxes. I might be interested in what other peopel believe as an academic exercise but its very uninteresting to be the negative of that, how would you talk about an unbelief?

I have Christian friends as well and know a lot of Christians. Most don't take that holier than thou attitude with me and those that do I avoid. I have neighbors I do everything I can to avoid.

Anti vaxers, flat earthers, religious people, they all need educating. But stupid does not want to learn, so I don't waste my time.

They need your money.

Religion is dangerous because people want to force it on you

I agree. My non-belief is mine and mine alone and I do not try to persuade anyone to think the same way that I do. I expect others to afford me the same respect and not try to push their beliefs onto me.

What one cannot tolerate in oneself, such as doubt in one's own convictions, one ususally cannot tolerate in others either. So, to remove this uncomfortable mirror from one's sight is most reassuring.

I have a friend who was a "fundamentalist atheist." When I pointed out to him that he was just as critical towards towards any type of spirituality as being evil as fundamentalist religious people were towards anyone who didn't believe as they did, he didn't get it. He'd post these huge rants on Facebook that sparked very heated debates. Then one day he got it, and suddenly became very humble, and the rants stopped.

Atheist here ... Of course there's no need for "missionary zeal". I think you may be drawing conclusions from a skewed sample. In every day, real life, I am indifferent to religion and don't bring it up unless someone else does, which has happened exactly twice in the past quarter century, and even then, it was a passing exchange. In my online life I come to places specifically designed for the purpose of discussing and debating [a]religion, with other people who voluntarily come for the same reason. And then I have spirited discussions about a topic that interests me and that I care about in this context. No one holds a gun to anyone's head to have these conversations; I am kind but frank and if people want to confuse their beliefs with their personhood -- in general, if they can't stand the heat -- then they can get out of the kitchen. It's astounding how many people confuse simple disagreement with personal attack. Beyond all that -- atheism is nothing more or less than unbelief in any god(s). While it tends to be a knock-on effect of skepticism and critical thinking, atheists are humans too, and sometimes it's not a well-considered position, and not always logically self-consistent. Nothing about being an atheist immunizes you from being an asshat either. Anymore than anything about being a believer immunizes you. Lastly, remember that many atheists are deconverts and may have lingering regrets and personal pain and abreaction to the theism they have come out of, generally at significant personal cost. So you would expect many of them to be crusaders. I don't regard myself as a crusader really but I am keen to help fellow travelers in their journey out of faith. I do that mainly by posting the kind of information that lurkers struggling with these issues will find helpful -- the kind of posts I wish I has encountered more of in my own journey out of faith.

It seems to be mostly a part of the Christian and Muslim religions. They feel they have a responsibiliy to spread the message of "salvation", one reason probably being that there was no universal revelation, just a local one, from a chosen few individuals. Which really doesn't make sense if the message is of such great importance to mankind. You'd think their god would have performed the miracle of a universal revelation. And that there would not still to this day be some pockets of culture oblivious to the existence the Abrahamic religions. And of course some of them hate to see others doing just fine and dandy without subscribing to their agendas or being subject to their restrictions. The Muslims especially seem to be motivated by this sort of intolerance.

To each their own.

I try to champion skepticism and critical thinking rather than atheism. Give them the tools to shed their own belief rather than address them directly.