If everyone was atheist

[paulpablo]

If the world were like this one, with just the minimum changed for there to be no religion, then there would be less sexism, homophobia, primitive tribal thinking, unscientific thinking, etc., because religion promotes all of those things.  Just getting rid of religion would improve all of those.  Of course, that does not mean that all of those things would be eliminated, but they would all be reduced.

To give one example, in my case, when I was a Christian, I was against homosexuals.  Not because I had any personal interest, but because that was what my religion taught.  When the religion was eliminated, so, too, was my motive to have any problems with homosexuals.  I now don't give a rat's ass whether my neighbor is homosexual, heterosexual, or bisexual.

I still think there are too many cultural variables to consider along with the variety of religions this world has seen.  Greeks were religious yet they accepted homosexuality, Stalin was an atheist who criminalized homosexuality, I also believe that at points in Hitlers life he was anti religious and favoured science to religion yet he was also against homosexuals. 

I think most of the things in religions is just a reflection of culture anyway, the bible actually has more verses condemning shellfish than homosexuals, but the average American Christian won't give a shit about shellfish.

I would accept that it's quite likely that with the elimination of religion a lot of homophobic, sexist, unscientific ideas could be reduced but I couldn't be certain PURELY because the evolution of how cultures develop is so seemingly random and variable.  Think about all the crazy ideas, fashions, trends, wars, persecutions around the world that happen without religion.
Also if the question is asking what if every person who was ever alive was an atheist then there definitely would be too many variables to consider because I don't know what kind of culture the world would have right now without religion.