Kate appears to have some background in Arab world (unclear on this) but no real background in English sport horse disciplines as far as I know.
We have a big local Arab show. The Arab x WB “sport horses” can be lovely creatures that dont look very typy Arab. The saddle seat crosses are their own thing, and an Arab x DHH or Hackney could certainly get that result. Again, can be very nice horses of their type.
It’s possible that if Kate got her start in Arab world, she doesn’t see the knees and the flat croup as being undesirable for English sport horses. It’s also possible she saw DHH in Arab crossbreds. And then figured out that the really big money is in sport horse with European WB stallions. But she actually has no idea what conformation and movement you want in dressage, hunters, or jumping. Because she doesn’t understand the sport horse world, ams her eye has been trained on Arabian circuit.