The biggest anomaly in this is that the woman was a member of a hunt. Hunting is by its very nature a cruel blood sport.
It's not an 'anomaly' at all. Hang around long enough in the horsebox park at a large horse event and you just might see similar behaviour (though you might just have to hang around at several events to catch it, despite another poster's conviction that horse people are frequently vile to their horses). The only reason it was caught on video was that the hunt sabs were there filming; a far more common occurrence than people hanging round horsebox parks, filming, at major events.
I stress this because people are now conflating following the hunt with having a blood lust and being more intrinsically cruel to animals than 'normal' people. Which is absolutely ridiculous.
Most people go hunting for the sake of (hopefully) a good gallop across country, and a few jumps, in places where they normally can't ride. And, whatever you might feel about the disconnect between being kind to their horses and cruel to the fox (that might be hunted, because not all hunts break the law ass a matter of course), the few people I know who hunt, or have hunted, adore their horses (and their inevitable dogs) and would not dream of treating them as did the woman under discussion.
I wonder how many hundreds of hours of filming hunt sabs have done over the years, throughout the UK, just to catch this particular brief snippet?