This isn't really that big of a deal and happens all the time. The difference is that this is a very publicized event. Players have, through no fault of the umpire, managed to attribute their loss to officiating and get into arguments and just not get along with certain umpires. By stubbornly forcing that umpire on that player shortly after an incident you'd be intentionally introducing a disruptive element into the match - which, by the way, is exactly what people criticize Ramos for doing. It makes more sense to let things cool down for a bit first. To be honest, when I first read this thread I assumed it was to say that male umps would work all the men's matches and female umps would work all the women's matches.