I'm at work and took a quick look & stopped at Iran and Afghanistan being Enemies. Unless I'm reading the bolded red part wrong they are saying the US indirectly handed Iran victory over its Afghanistan enemies? When was Iran an enemy of Afghanistan?
That part also confused me but (a) the author, Abdelwahab El-Affendi, a Professor of Politics in Qatar, probably understands the complex politics of that region better than any of us; and (b) that detail is inessential to the larger point just in this excerpt.
I don't understand Mideast politics well, but the Sunni-vs-Shia conflict seems to be very important. Shi'ite Iran was indeed given a Shi'ite (formerly Sunni) Iraq for free, and there is a de facto alliance of Syria, Russia and Iran; and they are opposed to Sunnis.
ISIS, Al-Qaeda, and most Afghans including most Taliban are all Sunnis, so are all natural enemies of the Russia-Iran-Syria axis. (ISIS is Wahhabist, like Saudi Arabia.) I think El-Affendi is correct that the U.S. actions in the Syrian and Iraqi conflicts have implicitly helped the Russia-Iran axis.
The Kurds, mostly Sunni, are one benign group in the region and the U.S. has betrayed them repeatedly. The U.S. got involved in a complicated game of chess and behaved as though they didn't know which pieces were on which side.