Hitting a ball the has already hit the ground...

[SanDiegoSteve]

Originally Posted by CoachJM

Perhaps they are exhausted by their efforts in maintaining a perpetual, stoic calm under any and all circumstances in the games they officiate, and they come here to "vent" or "unwind" as a release.

This is most likely the case. Also, it is usually considered unseemly for an umpire to dump all over a fellow umpire, and it comes as a genuine surprise when it happens. And then sometimes, certain people can't take constructive criticism without resorting to name-calling, personal insults, and baiting into retorts, even thought they don't really know a thing about the person they are attacking.