I find the ad style refreshing.
And since what she says in the ad is pretty much backed up by the videos, I’m okay with it.
I don’t think that’s throwing shade at the rider. It’s a big, strong horse, and if the fences are little, there’s nothing to back him off. “Petite adult” may simply mean the rider likes the physical strength to hold him together on course.
Here’s what I would find offensive: marketing this same house to a timid junior or amateur as a schoolmaster, and either drugging it or lunging it to death so they can safely get it around 1m/1.1m, and then charging them for training board when that no longer works.
That scenario is actually a whole lot more common than being upfront about what type of rider the horse needs.