Here's my perspective:
When I see one or two frags or colonies with no polyp extension, or color loss, in a tank of otherwise healthy and thriving SPS, I would question why only they would degrade if my problem was water quality, or other parametric effect. I do not believe that red bugs are opportunistic scavengers, I believe they are predators.
We can talk about cause or effect all day, but the facts are that they are undesirable, and should be eradicated when seen. They should certainly never be ignored or left untreated.
How, otherwise, at the very least, could you guarantee that any frags shared out of your tank, will not be a vector for the contagion to other reefers' set ups?
The other thing I have noticed, is that while I certainly see some pod loss, with interceptor use, the overall population seems to bounce back with a vengeance. Perhaps culling the herd is not a bad thing in those crustaceans we do want to encourage.