All political parties in Ireland along with all the victim groups of the troubles from Ireland to England along with pretty much the whole population of Ireland both Unionist and Republican are completely opposed to the amnesty, what can do they do about it realistically? If the British government clicks their fingers and says that's that then what can they do about it?
The forthcoming amnesty bill would prevent all prosecutions for crimes during the troubles and shut down all further inquiries into the state’s actions during the Troubles, such a law would have prohibited the Saville Inquiry into Bloody Sunday and other inquiries into state collusion with loyalists which many believe is the real reason for this amnesty.
Although Boris Johnson seems to be getting most of the blame it's extremely unlikely he and a few of his colleagues decided out of the blue to take this decision, he more than likely done this after being recommended and convinced to do so by MI5, the most powerful people in Britain.
During the troubles the intelligence services worked closely with loyalist paramilitaries as part of a psychological warfare campaign against the IRA, one of the most infamous was the killing of human rights solicitor Pat Finucane who was at the time investigating state collusion with loyalists when MI5 set him up for assassination, this case stands out because it's one of the only cases that have been proven beyond doubt, although the state is strongly suspected of involvement in hundreds murders in collusion with loyalists.
There is a good documentary on Netflix about the Miami showband massacre, it talks about Robin Jackson the most ruthless killer during the whole troubles who is estimated to have been involved in the murder of 150 innocent Catholics and lead the men who committed the Dublin Monaghan bombings and the Miami showband massacre, it provides evidence that he was an agent working for MI5 and RUC special branch and that the Miami showband massacre was signed off on at the highest level of the British intelligence agencies and that government of the time likely knew about it, the documentary claims the intelligence services set this up because they wanted the Irish government to seal the Irish border as the IRA in the South were launching attacks against the army and then fleeing easily back across the border.