The word “atheist” is used by religious people as a pejorative in the same way that some people (the religious ones) used to use words like “gay” or “queer” against another group of equally reviled folks. (and woe to us gay atheists!)
There is nothing wrong with not believing in god – except to the people who do – they seem to take it as a personal affront to their beliefs when they are not shared. As if it invalidates them somehow.
You would think that believers would be threatened more by believers of other faiths – but instead of all out crusades as in previous centuries – in the last century the veneer of civilization made uneasy allies of religious groups with the ridiculous idea that they are all about the same god but worshiping in different ways.
This makes no sense, since each god demands worship in a particular fashion, with dire consequences for failure.
The reason that atheists, gays/lesbians, childless by choice het couples or single moms by choice are so threatening to the righteous religious people is because these groups are dangerous to the religious idea that you must marry an opposite sex person and breed children in order to be happy, successful and worshiping the deity of their choice.
That atheists, gays, lesbians, bis and trans, childless or single parents can and do live happily, morally and successfully is threatening and dangerous as it is not compatible with the religious creed that one can only be these things when you are enslaved ….er … worshiping the correct god.
Since the religious righteous live in terror for themselves and their children – they do not want their children to grow up and be anything that doesn’t conform to the norm. Especially when a grown “child” not being what their parents were/are appears to be a rejection of what the parents stood for.
Often without any awareness of the irony if the parents deviated from the grandparents….
So, let’s be very clear.
Being an atheist is not a rejection of people who are religious. It’s a rejection of the religion.
People who are secure in themselves and their beliefs are not threatened or concerned with what others believe or how they live.
People are entitled to have whatever belief or not that they want – where civilization breaks down is when one person/groups’ beliefs are imposed on other people. Which is why actual separation of church and state are essential to a democratic and free society.
If you’re not convinced, compare the Scandinavian countries and to some extent, Canada, against any religious theocratic country – in terms of crime levels, health care, standard of living, civil rights and pretty much any measure.