I use by Quest exclusively for working out (FitXR + some Beat Saber), around 1 hour a day, 5 days/week. I don't have any neck problems at all. Maybe you just have a weak neck?
Given that a VR headset places an unbalanced, unusual, not insignificant weight (pulling down the front of the head) on delicate and vital structure that is the neck, I think the onus would be on the manufacturers to show that it is safe, rather than vice versa. Everything else you wear on your head is either balanced (helmets) or very light weight (glasses).
Manufactures do believe they are safe. There are over 20 million of these out there. OP said it caused serious neck injuries. Doug asked for a single source.
FWIW, as someone who logged between 175 and 200 hours of usage with a Quest 2 playing Beat Saber (a high-movement game) last year, I’ve not experienced any issues.