The exclusion was because the World Breeding Federation for Sports Horses is specifically for breeders producing sport horses. And thoroughbreds for the most part are bred specifically for racing and those competing at the top levels of sport are primarily fall outs from the racing industry, not bred specifically for “sport” disciplines. So no huge conspiracy here. And I don’t think the various Jockey Clubs are members of any of these organizations because that type of “sport” is not the focus of the Jockey Club.
However I do think it is silly to list a thoroughbred as breeding unknown or “other”, even if it is an OTTB. At this point in time there are very few thoroughbreds at the top of the sport except for eventing and even in that sport they are decreasing at the top level. But even so I think that if the breeding is available it should be noted.
I think that TBs are WB breeders dirty little secret, kept hidden. If one looks at even dressage WB pedigrees, it is surprising how much “blood” is to be found, if often a couple of generations back. Look at the record of Heraldik xx who produced more than Eventers.
The WB of today will not be around for long if people don’t keep breeding TBs for sport. They will revert back to old style heavy horses.
I get the reasons why they excluded TB breeding info, but I DON’T get it because they very WBs they’ve promoted wouldn’t exist without the TB.