Can anyone tell me WHY we are still at war?

Uhh...like any man...we dive in better than we withdraw.
KISS

But to keep it brief...
We got in because the neo-cons wanted to attack the leader of Al Qaeda after 9/11 (the excuse), everyone else in a frenzy & patriotism went along with it.
We got distracted by the Iraq War, which one part went in for WMD (the excuse), the other for oil (the reality).
So after we slowed down and stopped that...we refocused on Afghanistan...because of the Taliban (the excuse) but it was for Nukes in Pakistan (the reality).

The only reason we're stopping, we cannot control Pakistan after all...leaving to Indian & China to resolve.
Corruption of the leaders in the Host-Nation, incompetence/ignorance of the citizens of the host/nation, war-wariness, budget & cost,
and of course, negative politics both at home, there & globally
and finally the Taliban are like cockroaches. (now you know why they survived the Soviets, with US assistance BTW)

To sum it up, it's complicated.
Inane...but complicated.

And of course, the US will leave a base or two there like all the other rabbit droppings we've left were we've been.