“[The court] agreed with his argument that potential jurors were improperly dismissed from the jury pool after saying they personally disagreed with the death penalty but would be willing to follow the law and impose it.”
If those were peremptory challenges then not seeing what the problem is.
As a former prosecutor and death penalty defense counsel...having handled about 50 death penalty cases in my career...this was the right decision legally. If the court excused jurors “For Cause” because they expressed reservations about the DP but said they would follow the courts instructions and the law, they should not have been excused. Now if the state excused them via their limited number of preemptory challenges...then it is the wrong decision. Preemptory challenges can be used for any reason other than to specifically exclude jurors based on race. But if it was “for cause” removal of jurors for expressing reservations, that is definitely improper.