I wonder if this is a reply to the anime director's request to the internet to "stop lewding the horse girls".
There are people posting said request from cy in the comment section. But hey, remember Ellen Baker? Pleaing never works, and backlash will happen. It's the fucking internet after all.
These are actual horses enjoying quite some amount of fame, their owners may not like the possible rule 34 trend. The anime is extremely tame because of this, with a strong focus on sports and no nudity scene or "sexy" design at all. If this trend ended up like Ellen Baker trend, cy's future copyright negotiations will get considerably more rocky.
Nice bondage, but why aren't they nude? There could also be some guys standing behind them just touching or fucking them. I mean nice image, but a bit incomplete