Neither team could be separated after 80 minutes as both teams ran in four tries in a thrilling contest, which went through two periods of golden point before ending in stalemate.
Ex-Wests Tiger Aidan Sezer had the chance to snatch victory for Hull with 19 seconds remaining of normal time after Lewis Martin dived over in the left corner, but his conversion struck the near post for the second time in the match to send the game to golden point.
It was this decision which particularly irked the Leopards boss, as video referee Jack Smith awarded the 79th-minute try with Martin's foot close to the touchline.
"Not a try, never a try in a million years," ex-Kumuls and former Sydney Roosters star Lam said. "I've looked at the video a hundred times and the foot is out, like what are we doing?
"My job is on the line when we don't get those decisions right.
"Everyone in the world can see it, what's inconclusive there? Like when they went for the captain's challenge, if it's inconclusive isn't that an unsuccessful challenge? Don't you lose the challenge then?
"How can you be inconclusive? If the third ref can't get it right, maybe we should send it on to another referee in a box somewhere else to make the decision."
Controversy ensued when Lachlan Lam's restart for the second extra period was collected by Tom Briscoe with his foot appearing to be in touch. Video referee Smith, however, said the decision was inconclusive and Leigh were awarded a scrum instead.
He added: "Lachlan Lam's kick goes out on the full. Everyone in rugby league knows that's out on the full, what are we doing?"
The Leopards came into the clash as one of only three teams with a perfect record after three rounds but could not make it four out of four, despite taking the lead on three occasions.
However, Lam sung the praises of his Super League-leading squad following short turnarounds in the victories over Huddersfield and Catalans Dragons.
"We've hardly trained just to save bodies on a five-day turnaround and then a six. I'm proud of the players, I thought we'd have won the game three or four times when you are in front," Lam said.
"But credit to Hull, I think they showed courage; I thought they were awesome tonight, they couldn't have done more.
"I guess in the end, it was a fair result."
Hull head coach John Cartwright was equally perplexed about some of the officiating after Sezer and former Canberra Raider Jordan Rapana were sin-binned in quick succession for high tackles on David Armstrong in the first half.
"I'm still getting my head around what actually constitutes a sin-bin, because there were a few after that where Leigh came up with a couple of high tackles and they weren't penalised," Cartwright said.
"There was a crusher there that went on report but no penalty, so just trying to get my head around the consistency of it."
On the contentious Briscoe outcome, he added: "Still trying to understand that if his foot wasn't on the line it should have been play on, because if his foot was on the line, it's a penalty for us - so I just need clarification."
Cartwright hailed the "spectacle" and the home support as the Black and Whites climbed up to fourth in the table.
"It was such a spectacle," the Australian said. "My phone is absolutely full of messages from back home full of compliments.
"I have only been here a short time, but the crowd tonight, I have no doubt that they lifted the players when they had nothing to give. It is our 14th player, it roared just when we needed it."
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