Actually I have noticed a lot of kush strains are listed as having genetics from afghani or of east indian decent personally the very first strain I can remember that had the kush flavour was Durban poison back in the mid 80's.You say I don't know, but do you? All you know is what people tell you.
Sure there is a region called Kush and most of us already know that. But have you ever been to a place where things grow wild? Noting is pure. Nothing is naturally good. If you seen where your Red Delicious apple come from you would not believe they are both apples. And landrace weed that are wild are as unstable as the original apples. The biggest job of most breeders is to isolate qualities and breed out the bad. Your Chihuahua dog come from the wolf believe it or not.