I am certain the ’cuda hit the glowstick thinking it was some type of food. I guess it would resemble a popular artificial lure used in the Keys, particularly for catching barracudas on the flats. They come in neon colors: lime green, hot pinks, purple etc, generally made of nylon tubing or rubber, and are very effective.
Also, there was an instance in the Florida Keys, where a diver was killed by a cuda that bit the light attached to either his head or a helmet during a night dive. So lights, flashy stuff etc are all very enticing to this species.
I don’t dive at night so I can’t speak to their behaviour in the dark. But I have had innumerable encounters with single as well as schools of big barracudas. They are curious and will fearlessly follow or face a diver until they lose interest. But I have never encountered any aggression , inspite of the fact that I have speared dozens of them. A few of them as large as 4’. I don’t eat the bigger ones but upto 30" in length, they’re delicious! I’ll see if I can post a pic.