The 'insurgency' in Southern Thailand is not going to be stopped through the use of force only. It is going to be stopped the same way the communists in Thailand were stopped twenty years ago. This is a combined effort to reduce the desire to fight among the 'insurgents' and is going to take time. This is done through education and when needed, killing them.
I am curious where the author got the information that the two Marines were 'undercover'. Marines do not operate covertly. That is done by others.