Chairman Glenn Wahlstrom told the Weekend Herald he had seen some of the offensive messages.
"He has gone through quite a bit. There are underlying issues [some people] have undertaken around Facebook and Twitter sites that are pretty nasty.
"I saw it and it was absolutely disgraceful ... 'Get you' type stuff."
Mr Wahlstrom said the referee had been assessed by a doctor, but still had headaches several days after the assault.
Immediately after it, "he did suffer vision loss, momentarily had instability on his feet, felt he'd become unconscious at one point, had facial bruising and a cut lip".
The referee had asked for privacy.
Otahuhu coach Temu Faireka said he would be speaking to the players over the next few days to see if they would appeal against the judicial committee's decision.
Mr Faireka had been hoping for a punishment less severe than lifetime bans.
"I'm upset about it - first of all being banned for life from the game of rugby and then going through potentially ... police interviews.
"There could be another penalty imposed on them."
He said the game started late, and during it, the referee gave several yellow and red cards to his players.
A yellow card sends a player to the "sin bin" for 10 minutes; a red card sends him off for the rest of the game.
The fight erupted near fulltime when a penalty try was awarded.
Mr Faireka said some of his players ran onto the field to confront the referee, but says he did not see him being hit.
"That's when things went a bit loose."
He ran on to the field to try to break it up, and later apologised to the referee, who did not want to speak to him.
He said he did not condone violence, but believed the players were "provoked" into acting the way they did.
One player, 19-year-old Fonga, said the team were frustrated by continual red cards that he said came without any warning.
"The ref was one-sided. It's because we're islanders and they were palagis," he said.
Mr Wahlstrom said the claim had "no substance" and didn't believe it was an issue.
Both teams had many Pacific Island players, so he didn't see how Otahuhu could pull "the race card".