You have missed the pointFor someone who so frequently, and correctly, points out that there's a lot of over-stating of the benefits of helmets by some organisations with an axe to grind it's odd that you've fallen into the same trap. There are only about 3,000 cyclists killed or seriously injured a year in this country in total. And any head injury causing concussion or worse counts as a serious injury. That includes all kinds of injury - not just head injuries caused by motorists.
You'd be verging on hyperbole if you said that there were "thousands a year" of cycling KSI in total. "Thousands" normally implies rather more than three thousand. Strip out all the injuries that are not head injuries caused by motorists (only about half of cycling injuries are caused by motorists) and there certainly aren't thousands.
I'd also disagree that there is a lot of blame-passing, or that there is a lot of benefit to the "motoring lobby" (which I'd argue doesn't really exist except as a fairly amorphous blob) from doing it - but those are matters of opinion rather than fact.
These are the claims that are being made, not my claims