to Wikipedia, the Socialist Workers' Party (SWP)
"[...] used to call for a vote for Sinn Fein in the North up until its party conference of 1995, when it was argued that the Adams/McGuinness leadership of Sinn Féin were moving to an accommodation with imperialism. It opposed the subsequent Good Friday Agreement, arguing that rather than ending conflict in the North, the GFA was 'institutionalisng sectarianism', creating two competing communities and political leaderships, both nationalist and unionist, which did little for working class people.
Following riots in Dublin on 25 February 2006 by republicans protesting at a planned 'Love Ulster' parade, the SWP issued a press release in which it expressed its full support for the actions of the rioters. According to the press release, given the wider context of (apparent) working-class alienation at the hands of the capitalist political establishment, the riots were completely justified: "socialists do not join in the condemnation of young working class people who riot against the police- especially given this wider context." Also, the SWP claimed that the 'Love Ulster' march was purposely planned by Michael McDowell, the Minister for Justice, as a provocation to republicans to riot, and thus further blacken the republican movement, of whom the Minister is a most vocal critic."
While it's arguable as to how McDowell could be so naive as to believe that the 'Love Ulster' loyalists could parade without trouble through the streets of Dublin, the responsibility for the rioters' violence lies entirely with the rioters (Garda heavy-handedness aside). Maybe some of the SWP folk out there could comment.