"This is rugby league and we will not get everything right. We're doing our best but it's not easy," Greenberg said.
"Decision of referees and match officials are in real time.
"Them asking for two points is not going to happen. It was never considered."
In addition to the gut-wrenching defeat, that stretched their losing streak in Melbourne to 15 years, the Dragons were unhappy they had to defend for the last 30 seconds with 12 men after back-rower Joel Thompson was withdrawn under the new concussion rules.
Coach Steve Price and veteran winger Jason Nightingale both said this week their team had been penalised for adhering to the rules, prompting calls for the introduction of an 18th man on the bench.
Greenberg praised the joint-venture for taking the concussion law seriously but said there were no plans for any changes to the interchange numbers.
"I was really pleased with a number of clubs over the weekend, particularly the Dragons," he said.
"They were making sure player safety was put first and foremost and made sure they were taken off when there was head knocks.
"That is the exact application and how the policy is.
"How that applies to clubs and how they use their interchange is up to them."
Nightingale has urged his teammates to put the injustice of Melbourne's try behind them and get their NRL season back on track.
Following a strong start to the campaign that yielded three successive wins, the Dragons are 3-3.
Price's side will host the Warriors on Saturday and Nightingale said dwelling on what could have been could work against them at Kogarah Oval.
"The evidence is there and it was pretty disappointing, but that's rugby league," Nightingale said.
"We really have to focus on the good things we did in the game, which were quite a lot. If we keep thinking about it, then it's not going to help.
"The short turnaround is the best thing after a gut-wrenching loss. You don't really have time to think about it as you have to move on and prepare for the next game."
