It seems unfortunate to me that people are assuming the OP is the author, and attributing the author’s opinions to the OP, when (some of) what the OP is actually saying does have merit.
it does seem like USEF and EC are using terms like DEI to appear progressive, but their actions don’t back up that they are really interested in real changes to becoming more inclusive, just like they claim to be about reducing abuse in the sport (both to humans and equines), but other than when Safesport steps in, what are USEF and EC actually doing?
It seems to me that the OP wanted to use the book as a talking point more than that they agree with all the points of the author.
I also think that people claiming modern sport’s history is military is ignoring how much the sport has changed since those days - modern showing seems very far removed from that history, and modern sport and rules likely were shaped by the wealthy vs by the military.