I'm not sure about your point about Saudi Arabia though since secular humanism was the environmental faith position where I came from.
Really - so when and where were you born then Vlad.
When I was born, in the mid 1960s in England there was a default societal assumption that there was a god and that that god was a christian god. It ran through most of culture and society in which I grew up - most notably within schooling, which was without doubt biased towards a clearly christian viewpoint even though every school I went to was non faith. We had hymns and prayers, services in the local cathedral. RE which focussed mostly on christianity with 'other' religions described just as that, 'other'. I don't believe that my schooling ever made it clear that people called atheists even existed, nor was the notion of humanism mentioned or discussed, likewise secularism.
So I've no idea when and where you were born - perhaps you'd enlighten us please.