Because they are originated from Afghanistan.
To speak of a group of people from Afghanistan, you would say, "Afghans." The word Afghan and Afghans are proper nouns and are always capitalized.
The answer is "Afghans"An afghan is a person with an Afghanistani Nationality.
Afghan Biscuits are a favorite home-baked treat that seem to have originated in New Zealand. There does not appear to be any memory as to why they are called "Afghan" Biscuits.
Afghans call it afghani clothes
People of Afghanistan may be called Afghans or Afghanis (compare to Pakistani). The adjective form is also Afghan or Afghani.
Because afghans dont believe in evolution
The war isn't over but I predict that Afghan will lose.
an understanding of afghan culture
Afghans won this battle and british defeated....
Afghan or Pashtun woman. Can also means Afghans or Pashtuns plural.
Pakistanis claim that most street crimes are commited by Afghan Refugees
Quoting the Afghanistan Peace Organization (http://www.afghanistan.org/): "People of Afghanistan are called Afghans, not Afghani. Afghani is the name of the currency used in Afghanistan."