GAA President Jarlath Burns said that during the Troubles the people of South Armagh feared the night because of rogue police officers and soldiers working with loyalist paramilitaries.
He said the British state had been complicit in the murder of its own citizens.
A member of the local Silverbridge Harps GAA club, he was speaking at a vigil last night to mark the 50th anniversary of a gun and bomb attack on Donnell's Bar in the village.
Trevor Bracknell, 32, Patsy Donnelly, 24, and Michael Donnelly, 14, were killed in the attack on Friday 19 December 1975.
It is believed it was carried out by a UVF unit known as the Glenanne Gang, which worked with members of the RUC and the Ulster Defence Regiment.
The GAA President told several hundred people at the candlelit vigil that the attack changed how people in the area lived.
"For years afterwards, many of us feared the night. We feared the sound of a car slowing on the road," he said.
"We feared the circling light of RUC and UDR patrols, because we knew what often followed it.
"We knew that the men asking for names and addresses were the same men, or closely connected to the same men, who were murdering our neighbours.
"They moved through South Armagh with confidence, armed not only with weapons but with intelligence gathered through official maneuvers and patrols."
The GAA President said the men were members of a group now widely referred to as the Glenanne Gang, which is believed to have been responsible for 127 murders, many of them in South Armagh.
He was strongly critical of what happened after the attack, saying crucial lines of inquiry were not investigated and critical information was not shared with investigators.
"Families were left not only with grief, but with silence – a silence enforced by the state," he added.
"Let us say this plainly, standing here together: the state being complicit in the murder of its own citizens is something that has never been properly explained, never fully atoned for, and never sincerely apologised for.
"Secrecy was used to protect institutions, not people. Intelligence was withheld, warnings were ignored. And the price of those decisions has been paid by families year after year, especially at Christmas."
An independent inquiry codenamed Operation Denton is examining the activities of the group referred to as the Glenanne Gang.
Its full report, which will include details of the Donnelly’s Bar attack, is due to be published early next year.
Mr Burns said the truth must be fully told.
"What happened here must be known. Not only the violence of that night, but the injustice that followed – the silence, the denial, and the failures that deepened the suffering of families and of this community," he said.
"Not because we seek revenge. But because justice matters. Because memory matters. And because silence has already taken too much."
