It reminds of an alleged exchange between an archbishop and some sort of heckler who said:
"You're only a christian because you were raised that way"
And he replied: "You only think that's a good argument because you were raised that way"
If that line of argument convinces you and you think all reason and empiricism is no better than cognitive bias, why ever discuss anything with anyone?
I'm not sure that line entirely convinces me, but I think the people who use the cultural contingency are generally being hypocrites about it.