I think it is propaganda and don’t believe it. Anyone who has raced motocross bikes can testify to how hard it truly is to break a human neck. If it was that easy every motocross racer who took a bad tumble would have a broken neck, helmets wrench a neck harder than any cell environment could.
Keep in mind that the hyoid bone is in your throat...basically your adams apple. It’s not going to get stressed in a bike accident. But it does get stressed when you’ve got a rope around your neck, or someone’s hands. That’s why a broken hyoid is considered a telltale sign of strangulation. Hyoids in older men are also more prone to breaking because they ossify over time. These are factoids I’ve gathered from a few articles posted here on FR.
What’s bugging me is the examiner’s use of the plural “bones”. To me, strictly speaking, this would mean that not just the hyoid but also vertebrae were broken. And here I agree with you that it takes some pretty extreme forces to break vertebrae, forces that are unlikely in my non-expert opinion to be present in either a kneeling self-strangulation OR a manual strangulation by another person. I think you’d only get forces like that in a drop hanging but they’re saying that’s not what happened.