When you assume a trait or action of a small sample of a group applies to the whole group. I'm basically agreeing with the post, just explaining what the reasoning for it is, and that it is wrong to judge all muslims based on the actions of a few, and the same applies to cops.
That said, the larger picture, stopping it spreading into south-east Asia, was accomplished, weather due to the Viet Nam war itself, or because it was nothing to worry about I don't know, but I would give you that one