When working animals are handled as if they were engines, their suffering drops out of sight even when it happens in plain view. Making their experience visible and tangible is the first step to treating them differently. Even sympathy for them tends to be framed in terms of usefulness rather than their own sake.
Everyday gear chosen for looks can inflict steady pain on the animal wearing it. A strap that hauls the head up into a stylish arch leaves the neck aching past bearing. When owners see that cost, such fashions can be abandoned.
A working animal's fate depends less on its own worth than on who owns it and what work it is sold into. The same horse can pass from a gentle, careful master to the hard grind of city delivery and cab work, its treatment worsening as it moves down the social scale. Kindness or cruelty is set by the owner's circumstances and character, not by the animal.
Learning to treat horses with patience, sympathy and understanding is practice for treating people the same way. The habits that make a good master of animals (attention, restraint, respect for another's pain) are the same ones that make a decent person.