Question:
I don't doubt the credentials, but I do challenge you to provide the basis for some of the numbers. I could care less who is writing, the information submitted is still subject to scrutiny and challenge.

E.g., that 30mil riding number with 50k injuries. Of those supposed 50k injuries, how many fatalities and how many head injuries? The way the numbers are presented, the author would have the reader assume a very high amount! Such may be, but the figures presented, without a citation to source, leaves the "facts" subject to serious question.

It is easy to point to a small sample of 30 and then declare "OMG, there is a 20% chance of this being the case of those 50,000 of the 30 million citizens riding!! We have to do something right away!! OMG!!" It is also a specious argument.

Answer: Looking at what information it does present (there's a slight lack of data - How many total bodies in the sample being the largest and most glaring to me - and how many total injuries were there versus how many rides taken? - If I come off a horse and sprain my wrist, I doubt I'm going to call the ambulance, ferinstance) would tend to support my opinion that head injuries are the least likely outcome when "horsing around". Based on these numbers, you're twice to three times more likely to mess up your arm than your head, and 1.5 to 2 times more likely to mess up your leg.

Which tends to follow with my own personal empirical evidence. In my 30+ years with horses, both as a rider or teamster (and as concerned bystander/first on scene at multiple horse-related accidents due to my line of work as a dude-wrangler/saddle guide) I've personally experienced (and witnessed/tended) schmucked arms and legs multiple times, with arms and hands being the victim much more often than legs, but never experienced or witnessed first-hand a horse-related head injury of any kind. No, I'm NOT saying that horse-related head injuries don't happen. But my experience so far has been that they are MUCH less frequent than helmet proponents would like you to believe.