Not all is as appears and most of what you are reading above is incorrect. No a player did not go on the field after a heated exchange but yes a player threw a punch at an umpire after the game was over which is very unfortunate. Following the game the umps started to exit the field through the Coalfield dug out and there continued to be discussions over a bad call at home plate. There were several spectators that were voicing their opinions about the quality of umpiring during the game that was called and one of the umps hung around at the gate and very clearly told a parent to shut the **** up which just happened to be the mother of the player that threw the punch. The ump who was also a law enforcement agent also confronted another spectator (brother of player)and began to throw his weight around and tell brother he could take him to jail anywhere, anytime, for anything which provoked said player to defend his parent and sibling.
All of this could have been avoided if the umpire crew had just exited the field as usual and gone on their way but it seemed as if they were hanging around to provoke something. No it's not excusable one bit for any player to go after an umpire and he will pay the consequences but as an umpire and an adult you should not let the power get to your head either. During this entire episode the head coach is trying to get the ump to leave and even stands between the ump and angry crowd.
There are several videos around so look them up for yourself and come to your own conclusion