Because Trump being a businessman and not a pol and first term president he took on faith that the career pols, civil servants and military hacks were providing him with good advice.
Obviously, that was not the case. Afghanistan was just one of the ways that chaos manifested itself all the while lawfare actions in addition to a constant barrage of media rumors about everything from golden showers to being a Russian asset.
The deep state is a very, very dangerous thing. It killed the Kennedys as you will soon find out fully my simple friend
You're not even a US citizen lol. Stop whining FF s