Why would you assume that? My objection at the start of this sub-thread debate was horses for entertainment (which is the vast majority of them), not working animals.
I do have objections to animal cruelty in food production, but I'm not extreme about it - free range and organic is fine by me. Likewise as long as working animals are treated well I have no problem with them.
I also have no issues with companion animals like cats and dogs (except for the weirdos who practice inbreeding, like the Kennel Club), because their evolution and domestication was a very different process and they are symbiotic with humans. Again, though, only if they're treated well. Every house around me has at least one dog and I am very uncomfortable with how many of them are living.
I'm sure vegans and animal rights activists would find my position hypocritical, but that's where I land.
I know that most horsey people treat their animals well, but they can't deny that the whole horse world only exists for human pleasure, and if they think the financial incentives at the elite level aren't sufficient for a great deal of cruelty to be going on, they're kidding themselves. Air-conditioned horse boxes and the best food etc etc are ultimately about protecting the investment, and they don't preclude cruelty in training.