Will somebody please tell me why the USA coerced NATO to make war against Afghanistan 8 years ago?

Nato didn't make war against Afghanistan, but against the Taliban in Afghanistan, and the request came via the United Nations. The Taliban wre, and still are judging from recent events in the USA a terror group, the idea was to help set up a moderate Afghan government democratically, however as the Taliban are difficult to track down, it's taking many years, and costing many lives.