What's sad is we can never know how committed or opposed many figures would've been to socialism or social democracy. On both sides major figures like Collins and Cathal Brugha died tragically in the Civil War. We can guess based on their statements how much of the original Sinn Fein Programme they would've thrown out in time, but many of the arguments are based on a reflexive "no they never would be dirty commies" when the implication of even socdem stuff is mentioned.

The socialist movement also had to make itself part of the national revolution, it couldn't lead it or separate itself from it. Lenin himself strongly agrees with that assessment for ireland specifically. That was part of what Connolly meant when he said the Union Jack could be removed but without real revolution Ireland would remain imprisoned. The militant nationalist movement, despite its varied beliefs, was beneficial to the labor movement and both shared the mortal enemy of not the British but the Irish reformists.

the British managed to get parts of Sinn Fein to buy into a form of Home Rule and sell it to the population. The exact thing Connolly warns about years prior, that reformist nationalists and less nationalist inclined labor party members would fall for.