During WWI and WWII horses were used as Calvary and to pull artillery. Bigger horses, like the warmbloods that would eventually become the sport horses in the eq ring, were better able to do this work. Grey/ white horses were not suitable as they could be more easily spotted by the enemy. This left a higher proportion of grey genetics in these horses than would have otherwise been present. You also see this phenomenon in Irish Draught horses, perhaps even more clearly because their size, athleticism, and the fact that Ireland was undisturbed and thus able to continue breeding (the grey horses not drafted for the war).
I believe that a nice dark bay with some chrome is still the most desirable color trend. Colors, like pinto and Appaloosa, are considered “non traditional” and unless the horse is fancy enough to win as a chestnut, the coat pattern isn’t going to do it any favors. I haven’t noticed any prejudice against them myself though. I had an Appaloosa/POA large pony hunter when I was a kid, and if we got 8 spots we got a ribbon.
If you like a loud colored horse, have one! Just remember you have to get any white WHITE if you’re going to show!
