I think the OP said his bike never came with a spoke protector...so maybe the shop removed it (years ago).

Otherwise, I don't disagree with any of that post. In fact, I said something very similar. Within 6 months of purchase (or 1 month of a tune-up), the OP would have a decent case at getting some LBS support. If they haven't touched it in months, how do they know what happened to it? Maybe the owner tried to adjust it himself. Maybe one of the owner's kids banged the rear derailleur really hard in the garage and didn't tell anyone. I don't suspect either in this case...but I'm saying from the shop's perspective 'who knows'?

I don't think Cannondale is really on the hook here. 'Crash' isn't the right word exactly...but I sense that human error of some kind (rather than carbon/frame structural) caused the problem. The fact that it's a Cannondale dealer doesn't mean a whole lot. Is Cannondale training LBS mechanics?