Leanne Murray was 13 when she was killed by the bomb at a fish shop on the Shankill Road on 23 October 1993, along with eight other innocent people.
On Sunday, republicans held a commemoration for Thomas Begley, who was also killed in the blast when the bomb went off prematurely.
A plaque was unveiled by Begley's father Billy, who had previously told the media that they would have preferred a private memorial.
Also present was Sean Kelly, who accompanied Begley in the IRA attack. He received nine life sentences for the bombing but was released from prison in 2000 under the Good Friday Agreement.
He told those assembled for the commemoration he was "truly sorry for loss of life and injuries caused".
But speaking on Monday, Leanne's brother Gary Murray said he did not accept Mr Kelly's apology.
"He went out that day to do whatever he could, to commit mass murder," he said.
He and Leanne's mother, Gina, took part in a silent protest in the area on Sunday, as he said it was important that he made his presence felt as it had caused hurt and offence to victims' families.
"Everyone thought it was absolutely disgusting," he said. "They were tramping all over her grave, that is the way I look at it."
They were trying to hail Thomas Begley as a hero in my eyes, and he was no hero.
Gary Murray, victim's brother
Sinn Féin North Belfast MLA, Gerry Kelly, who was in attendance, said he would not glorify violence but they had a right to remember those who died in the conflict.
Mr Murray said he did not agree with Mr Kelly's previous comment that Begley too was a victim.
"My sister was a victim, he was no victim, he was a perpetrator, a mass murderer," he said.
"The victims are the nine innocent people that were murdered that day."
He said he could understand his parents had been hurt by the event but "glorifying a perpetrator is the wrong way of going about (remembering him)".
Mr Murray said he would be going to the memorial on the Shankill Road to remember his sister on the anniversary on Wednesday.
Reacting on Monday, UUP leader Mike Nesbitt said: "Thomas Begley made a choice. He made a very bad choice and the choice was to become a terrorist and plant a bomb.
"He died because of that, but nine others died and they were not given a choice.
"They did nothing more unusual than go out shopping on a Saturday morning, and because of that they died because Thomas Begley made a bad choice.
"That is the difference and to talk about devotion to your people is deeply offensive to me because what I want republicans to do is to try and persuade me that I'm one of their people."
The unveiling of a plaque commemorating and honouring Shankill bomber Thomas Begley exposes the emptiness of Sinn Féin claims to have concern for the victims of IRA terrorism.
Nigel Dodds, DUP
Meanwhile DUP MP for the area, Nigel Dodds, said the plaque was "morally wrong and grossly inconsiderate".
He said it "exposes the emptiness of Sinn Féin claims to have concern for the victims of IRA terrorism".
"Contrary to previous utterances from Sinn Féin, this is an IRA plaque commemorating Begley as a member of the IRA and glorifying his terrorist crimes, which included mass murder of innocent people," Mr Dodds said.
"To unveil such a plaque in a public street suggests that Begley should be viewed as some sort of role model.
"Sinn Féin may take that view but the vast majority of people remember the brutal and indiscriminate consequences of terrorism. It should not be publicly honoured. Terrorism should be remembered as evil, as misguided and as horrific."
Gerry Kelly said: "I think that people have the right to remember their dead and they chose their way to do that, it was a quiet and dignified remembrance of the life of this man.
"It was and very clearly put by Thomas Begley's father that it was not to glorify or celebrate the Skankill bombing. What you have to deal with is trying to move through and try to find a way to deal with this which causes the least hurt.
"I don't think there is a way of doing away with the hurt altogether."