It's not there for any reason.
It's there for a reason. The world has it's own history, traditions and etc., and even different countries do.
For example, there is strong sexism in Antiva and Rivaine, there is mild sexism in Orlais (which was struggled againsy by Aveline) and Orzammar (Silent Sisters).
There is some hints of sexism in Ferelden and other coutries, but not the exact amount of it than, say, in Antiva.
sexism toward women is "the norm"
Who said it was the norm?
It is not the norm for our society, It could be considered the norm for another. The "norm" is not always a good and fair thing, you know, it's just the thing that is considered acceptable by the majority.
BTW, there is sexism for the men, really. The Chantry 
Funny how excusable and permissible sexism and racism becomes in fictional fantasy and fictional sci-fi worlds
Oh? If you are against sexism and racism in fictional worlds, why are you not against, say, slavery? Or violence? Or ignorance at all?
Nobody here is saying ANYTHING about how the writers shouldn't have put slavery and violance in the game. Nobody here asks "Why did you make elves to be so hated because of their race? It's wrong!" No, the only things that botheres the society is that they PC will not get what they want because of these reasons.
So I suppose it's quite selfish.