Paul McGregor couldn't hide his displeasure at the match referees but has bitten his tongue to avoid another costly fine.
The St George Illawarra coach admitted he was "confused" after winger Nene MacDonald was controversially denied a first-half try by the bunker in Friday's gripping NRL win over South Sydney.
MacDonald had the four-pointer taken off him after video referee Steve Chiddy ruled that lead runner Tariq Sims had obstructed Souths halfback Adam Reynolds in the lead up.
Despite the Red V posting a gritty win, the Jubilee Oval faithful gave the officials a chorus of boos as they came from the field at fulltime.
Sims appeared to stop short of the line and the only contact between him and Reynolds was made by the Rabbitohs playmaker who stretched out his arms to push away from the Dragons back-rower.
"I'm as confused as you are," McGregor said.
"The two-defender (Reynolds) jammed in and when he jams, he's made his decision. He's come out of the line to make a decision and he didn't make the tackle. That's, that's all I'll say."
McGregor was careful with his words after last year being slugged with a $10,000 fine after describing the referees as "embarrassing and incompetent" following a shock loss to Newcastle.
The incident will only inflame debate about the obstruction rule which appears to be a source of confusion after Canterbury two weeks ago were given a try despite Will Hopoate taking out James Maloney in the lead up.
NRL referees boss Bernie Sutton subsequently admitted his whistleblowers got the call wrong.
Asked for his view on the MacDonald no-try, Souths coach Anthony Seibold said: "I'm not sure. I was happy with the call. So I'll say it's the right call."