>>513809155 (OP)
>solve the problem
There wasn't a problem. The east coast urban centres didn't fit will with how the IRA operated; they weren't launching these mass offensives to seize towns and cities, but were instead eroding British authority through isolated attacks until the area became ungovernable-at which point the Republican government took over.
In Dublin, invisibility of lead rebels was important as it allowed them to operate within the city and run the campaign from various safehouses; they had spies everywhere, and operated in secrecy.
>>513809965
The IRA has always considered the Republic of Ireland illegitimate and has been very firmly on the far left since the 1950s. It was already "left wing" in the 1920s, though, since Irish Republicanism is a left wing ideology. There has never been a "right wing rebellion" against British rule, unless you count medieval rebellions that were moreso about swapping out one foreign ruler for another.