I am Irish. I don't speak for everyone here, but the prevailing viewpoint I and people I've spoken to in Ireland on the matter was always that a united Ireland can only happen with the agreement and cooperation of the people of NI, not at their expense. The region is still quite fractured on what it wants; some see themselves as Irish, want to unite with Ireland, and effectively want no part of the UK. Some see themselves as British, want no part in Ireland, and want NI to be closer to the other UK countries. Then you have people who like the unique position NI is in, being essentially both Irish and British, although that sentiment I imagine is a bit strained with Brexit...
However recall that the NI border is a new thing, and Ireland was once entirely under the crown's rule. That the country was arbitrarily split (lets not discuss the actual reasoning right now, just making a point) was seen as a spit in the face, and republicans kept fighting. At the time the NI border was drawn, absoultely it would have been a more black and white issue. As time went on, as the region stabilized and gradually a new generation grew up as Northern Irish, not just Irish, not just British, things changed. and things are a lot more grey. While the sentiment that NI is Irish land, and Irish people is still here, the conversation around it is a lot more nuanced, and the idea of simply annexing it, kicking out the Brits in the bunch and instilling full Irish rule is... let's say idealistic at best, nationalistic at worst. A lot of people that say they want this will actually have a more nuanced (or flipant) opinion on this if you actually ask them about it. Which brings me to Sinn Fein, which I guess is the crux of your argument. They're our left wing party, also our republican/united Ireland party. Fine Gael and Finna Fail couldn't give less of a shit about anything but lining their own pockets. There's support for SF as a rejection of FG/FF, as a left wing party, and as the only party with any inclination towards a united Ireland. SF's current public stance is to hold a referendum on the issue, which a lot of people are fine and agree with, but they also have ties to the IRA which people generally very much don't agree with including SF supporters. I'm not sure how I'd even describe that, but basically, the desire of a united Ireland is fairly universal across all ideologies to different degrees (hell, even not wanting NI because it's a money drain is a valid viewpoint), where annexation or any other straight up agressive approach is generally handwaved because it's a ridiculous idea.
To make that long ramble short: it's nuanced, and it shouldn't really be just put in the left wing/right wing column without knowing a lot about the situation and the actual different viewpoints. Really though, it's a whole different ballgame to what's going on with this "Greater Albania" thing, and should be treated as such.
Irish people more generally support people wanted to gain independence/recognition. You'll generally find higher levels of support here for Palastine, Catalonian independence, even the Kurdish cause, than you would in other countries, because it reminds people of our own past. I'm sure most people here would support Kosovo's existance and outright reject the idea of "Greater Albania".
Of course, I don't speak for the Irish, and I certainly don't speak for the Balkans, but I wanted to give some kind of response.
www.rferl.org
www.reuters.com
www.thejournal.ie
