The only negative I see in the story is the fact that they let them “drop their weapons and run away” to fight another day. That part of the ROE is getting men killed.
Here, let me help. The Marines had been in a sustained firefight without relief or resupply. I'm sure a lot of them were low on ammunition. They were exhausted and probably out of water. A few were wounded, though none of them seriously. Even after killing 50 of the enemy, the Marines were still outnumbered nearly 7-to-1.
They had just won an enormous victory on ground they had been able to control. Under those conditions, you think they should have gone charging off into ground they were unable to control, in pursuit of a numerically superior enemy, and risk turning an enormous victory into an enormous and costly defeat?
Remember, at that point not even one Marine had been seriously wounded. At the Academy, you learn that sometimes, you have to let a few of the enemy get away. Hopefully, they might grow a brain and decide to go back to herding goats for a living.