Twelve months ago, Northern Ireland’s devolved Executive collapsed when the late Martin McGuinness resigned as deputy first minister, supposedly in protest at a badly administered energy scheme. The chances of unionists and republicans finally agreeing to restore power-sharing were damaged last weekend, after Sinn Fein MP, Barry McElduff, appeared to mock victims of one of the IRA’s most infamous atrocities.

On the 5th January 1976, on a road in rural County Armagh, armed paramilitaries stopped a minibus carrying textile workers who were on their way home from work. The gunmen shot dead ten men, all Protestants, and released one passenger, who was Catholic. The callous sectarianism of the ‘Kingsmills massacre’ was particularly shocking, even in a province that had become accustomed to brutality and murder.

Mr McElduff, who has a conviction for wrongful imprisonment dating back to the Northern Ireland Troubles, chose the anniversary of these events to film himself posing with a loaf of Kingsmill bread on his head. He then posted a video of his antics to social media.

The West Tyrone MP, who is known for his ‘idiosyncratic’ sense of humour, claimed he was unaware of the significance of the date and intended no offence, but Sinn Fein has suspended him from “all party activities” for three months and called his actions ‘indefensible’. It is, at the very least, a remarkable coincidence that this bizarre behaviour took place at a time when the massacre was once again in the news in Northern Ireland.

Families of the victims have expressed anger that McElduff, who doesn’t take his seat in Parliament because of his party’s abstentionist policies, has been let off with a meaningless slap on the wrist and will continue to receive a salary during his suspension.

Yet the MP’s buffoonery is just a particularly glaring symptom of a much deeper problem with the unresolved nature of Northern Ireland’s past. The peace process has required no contrition or self-examination from the most prolific perpetrators of violence, the Provisional IRA, whose political wing is Sinn Fein.

Republican leaders continue to participate in public celebrations of paramilitaries who were involved in some of the Troubles’ bloodiest incidents. Sinn Fein promotes the idea that the IRA’s campaign was justified and necessary, distorting history to imply that its aim was to win ‘rights’ and ‘equality’ for nationalists, rather than force unionists and the British government to accept a united Ireland.

In Newry, close to the border with the Republic, the nationalist-dominated council named a children’s play-park after Raymond McCreesh, who was caught with a gun used in the Kingsmills massacre. In 2015, McElduff even used his personal blog to suggest that McCreesh was a “hero and martyr”, whose efforts in the IRA should be rewarded with a Nobel Prize.

The victims of republican terror in Northern Ireland can scarcely avoid being confronted by Sinn Fein’s attempts to glorify its movement’s crimes. If they object too vociferously they are frequently portrayed as opponents of the ‘peace process’ or accused of obsessive hostility to the party, by its army of social media supporters.

High-profile victims campaigners are subjected habitually to torrents of abuse online. A prominent republican activist accused Ann Travers, whose sister was murdered by the IRA in a botched attempt to kill their Catholic magistrate father, of lying about having cancer. The implication was that she’d concocted a story about suffering from the disease in order to deflect from the paucity of her arguments against Sinn Fein.

This unpleasant atmosphere has practical policy implications too.

During seemingly endless negotiations with the DUP about restoring devolution, Sinn Fein cited as one of its ‘red lines’ a demand that inquests are conducted into the comparatively small number of killings attributed to the security forces, during the Northern Ireland conflict. The party can make this demand knowing that there is little likelihood of equivalent investigations into crimes committed by the IRA.

The police and other agencies in Northern Ireland simply don’t have the resources to examine properly unsolved murders attributed to republicans, which account for 70% of approximately 2,000 murders the movement is believed to have perpetrated. Nor is there any political will to do so. The peace process has been nudged along by ‘comfort letters’ and pardons issued to IRA suspects. There is a belief that prosecuting important figures in Sinn Fein would bring the shaky edifice at Stormont crashing down for good and possibly cause violence to return to the streets.

In contrast, the army and the RUC were involved in 352 deaths, many of which were the result of lawful actions. The security forces’ methods were sometimes controversial, leading to allegations of collusion, but their overarching aims were always to prevent loss of life, damage to property and Northern Ireland’s descent into civil war.

The lack of balance in ‘legacy investigations’ has allowed Sinn Fein to promote the notion, against every credible survey of the historical and statistical evidence, that the state was the main aggressor during the conflict. They have portrayed the security forces as the orchestrators of a ‘dirty war’, during which double agents conspired to goad paramilitaries into committing atrocities. In the republican narrative its as if the British government were, for its own opaque and Machiavellian reasons, fighting a war against itself.

These continuing disputes over how the past should be understood are holding back Northern Ireland politically, but they’ve also prevented its society from genuinely absorbing lessons from a violent history. The view that the IRA’s campaign was justified seems more mainstream now than when the bombings and shootings were actually taking place. Young people increasingly accept Sinn Fein’s claims that it is involved in a continuous struggle to protect human rights and equality against abuses by unionists and the British government.

The IRA has not yet even admitted that it massacred the workmen at Kingsmills. A front group called the South Armagh Republican Action Force claimed responsibility for the attack. However, the police were clear that IRA members carried out the atrocity, a finding that was substantiated by a Historical Enquiries Team report in 2011. The weapons used in the murders were later used by the IRA to attempt to kill RUC officers.

Barry McElduff’s sick ‘humour’ may have grabbed headlines, but it is a minor incident set against Sinn Fein’s wider campaign to distort history and justify the horror it inflicted. While its efforts continue to go relatively unchallenged, children in Northern Ireland will never hear a clear message that political terror here was wrong and unnecessary, which means that there will always be potential for fresh violence in the future.