"Once again, when the shoulder charge comes into play this bloke right here (he pointed to a picture of James) is mentioned," Ackerman said.
"Now he is dead as the result of a shoulder charge. I watched him die that day, it's not something I thought I'd ever have to watch.
"Now Billy Slater should be found guilty of a shoulder charge. I know there was no malice nor intent to hurt in this tackle. No one was injured. But a shoulder charge was used."
Addressing Slater, Ackerman said: "Why couldn't you wrap your arms around the bloke?
"You know the rules. Play by the rules. You are a great player, Billy, no one is denying that.
"You have won premierships. You have won Origins … You have done it all.
"If you happen to miss your grand final come next week because of a shoulder charge so be it."
Slater, who has played 13 seasons in the NRL - all for the Storm - announced his retirement earlier this year, and Sunday's grand final would be the last match of his career.