Joyce (32) was handed a life sentence after he was convicted of murdering John Paul McDonagh in court last week.
Mr McDonagh (18) sustained a fatal wound to his lower leg during a street battle outside the Enniskillen home of Joseph Joyce in April 2020.
But now, Joyce’s supporters have launched an online campaign claiming he did not get treated fairly by the justice system because of his past..
Taking to Facebook, a group called Justice For All claims that Joyce’s background ensured he could not receive a “fair trial” because of his history of bare-knuckle boxing.
The post claims that the fact he was a bare knuckle boxer was given as a “reason why he was fighting outside”.
“That is not Traveller tradition, it was a man defending himself,” the post reads.
“Leading up to and after the verdict of Mr Joseph Joyce, the media had created a smear campaign to tarnish his character by mentioning his history of Bare-Knuckle boxing(BKB), as if he were a barbarian of sort.
“But bare-knuckle boxing is a tradition within the Traveller community dating back generations.
“This should not be used to determine who Joe is as a person. BKB is a way of sorts for two families to end their grievances with one another, by doing so in what may look like from an outside perspective looking in as gruesome.
“Yet, if you took a minute to realise what it is, it is that two people meet, whilst having a referee for each fighter (Fairplay men), and having rules established (No kicking, biting or headbutting).
“There are a few ways of ending a fight, KO, shaking hands and calling a draw, the third way is giving best.
“For one fighter to say they have had enough, All of these ways are laid out that a fighter can walk away at anytime. The most common way is shaking hands and calling a draw.
“So for the media to consistently portray Joe Joyce as this "Feared Hulking Brawling, Bare-Knuckle boxer is a disgrace, When the majority of fights are settled by draw.”
In a trial that spanned three weeks, a jury of eight men and four women were shown CCTV footage which captured the fatal wound being inflicted on Mr McDonagh.
In the CCTV footage Joyce could be seen standing on the street outside his home.
Brandishing a slash-hook in one hand and plastic bottle filled with ammonia in the other, the footage captured Joyce engaging in what the Crown described as a "street battle" against brothers Gerard, John and Jimmy McDonagh.
The footage also captured Joyce administering the fatal blow to the back of Mr McDonagh's left leg.
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Despite receiving medical treatment both at the scene and in the South West Acute Hospital, Mr McDonagh passed away on the morning of April 13, 2020.
Since his arrest following the death Mr McDonagh, Joyce made the case he was acting in self-defence and was protecting himself, his family and his Coolcullen Meadow home from an attack by the three brothers, who were armed with a knife, bottle and garden spade.
However, the jury rejected Joyce's claims of self-defence and found him guilty of murdering Mr McDonagh.
The father-of-three, with an address at Clon Elagh in Derry, was also found unanimously guilty of wounding Gerard McDonagh during the same incident, possessing two offensive weapons - namely the slash hook and bottle of ammonia - and a charge of causing an affray.
Before the jury returned their verdict, Joyce crossed himself in the dock of Dungannon Crown Court sitting in Belfast, and after the guilty verdicts, he was handed a life sentence.
Mr Justice Rooney thanked the 12 members of the jury for their service, then turned to Joyce and said: "The only sentence that I can give you is life, and so we'll come back and deal with the tariff at a later time.
"You will be notified when that will be, and your bail is revoked, obviously."