There was a good reason for the Americans and us going into Afghanistan, to flush out Bin Laden and his cohorts.
Once that was done, it was all about helping the government to oppose the taliban and helping the populace in many ways.
Ultimately though, we couldn’t stay there forever.
When you join the army you don’t pick and choose the battles, so no it wasn’t a waste of lives ( unless you are a pacifist, what is the army for?)
A friend of mine lost her son there, he was Army through and through and incredibly proud of what he achieved there, as is she.