I think that at one time, perhaps, atheisim may have been a "negative ideology", that it was an "excuse" to live in the here and now and justify nothing to anyone BUT I do NOT think that is the case now with the majority that are atheists.
I think that the majority are atheist quite simply because they do no "believe" there is enough evidence (much less proof) for the existence of any god.
Right now there is a deep rooted morla structure that allows for an athiest to nbe so AND to be a morally just and righteous one.
Atheists do NOT see a need to get their morals from ANY religion.
I think that for a person that has concluded there is no god, that person can still be very healthy emotionally and morally and by that I mean they KNOW what makes them happy and pothers happy and they know what is right and wrong and do their best to do what is right.
I also believe this is the case BECAUSE of the good brought about by religion and because, IMO, we are all born with the ability to know, understand and teach what is right and wrong.