The full quote is "Dublin is also once again popular, partly due to the many people in the north west with Irish heritage - and it being a gateway to the United States."
Like it or not it seems that significant numbers of people head to the US via Dublin, so it seems reasonable that as the MEN views itself as an objective newspaper (we could argue for days whether it achieves that at all!) it should report that fact. I would imagine 99.99% of people reading the article will focus on the fact that it is a positive story for MAN, rather than the half sentence that mentions something that touches a nerve on here!
Now if they were reporting that MAN were having a push to persuade prospective US passengers that AA, UA, DL, VS, TCX and TOM direct from MAN was a lot more convenient that a stop in DUB then we would all be happy!