Why is NATO in Afghanistan? Is Afghanistan in Europe or North America?

Article 5 of the North Atlantic Treaty:

The Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all and consequently they agree that, if such an armed attack occurs, each of them, in exercise of the right of individual or collective self-defence recognised by Article 51 of the Charter of the United Nations, will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area.

Any such armed attack and all measures taken as a result thereof shall immediately be reported to the Security Council. Such measures shall be terminated when the Security Council has taken the measures necessary to restore and maintain international peace and security .

We know from September 11, 2001 that al-Qaeda's Osama bin Laden had suicide pilots aim three planes at the World Trade Center in New York and the Pentagon in Washington DC. A fourth plane was supposed to hit the White House. George W. Bush wanted to capture bin Laden for these attacks. He sent American soldiers to Afghanistan hoping to find bin Laden and also to overthrow the Taliban regime in Afghanistan which gave bin Laden a place to train his al-Qaeda terrorists. The US military removed the Taliban from power in Afghanistan. Bin Laden possibly went into hiding in Pakistan.

Some NATO countries currently have their soldiers in Afghanistan to try to keep out the Taliban. NATO is not looking for bin Laden in Pakistan. Why are NATO soldiers in a Afghanistan, a country located outside Europe and North America? Why is Canada "obligated" to be in Afghanistan? Forty years ago, why didn't NATO help the United States in Vietnam?

I think the North Atlantic Treaty is great for ensuring the security of the member countries in North America and Europe. If Russia, Finland, or Sweden wishes to attack NATO member Estonia, I would hope that Canada and the other NATO countries could come to the rescue against an invading IKEAn Viking navy.

Years from now, the United States will find another country into which it can send its military. Should the other NATO countries be obliged to send their soldiers just because the US needs extra military strength? NATO is great if it sticks to the core of the Treaty. Once it stretches beyond the bounds of the Treaty, it loses the cohesion of the member countries.