[officialtony]

It seems to me, based on all the information presented, that the two umpires decided that, excluding the assailant, everyone remained in control of themselves and did their best to prevent any further problems.
Call the police.
Arrest the assailant.
Remove him from the area.
But, if the umpires were comfortable continuing, I am in their corner. I don't see ANY reason to forfeit.
Even the assailants dad ( a parent ??? ) was upset at and disapproved of his son's actions.
It just sounds like everyone execpt the assailant was in the right frame of mind.
Play baseball.
After all, isn't that why we are there?