Why indeed! There have been reports that senior 101st Airborne officers were among the casualties. The attack sounds more planned than impulsive, like a "decapitation attack" on the 101st.
Whoever was in charge probably had the discretion to leave him behind but more than that (sending him home) would have been difficult because it would violate political correctness. Shouldn't be now, though.
And, to be fair, the officers have a lot on their minds. Dealing with one loudmouthed yardbird probably wasn't the top priority.