It’s worth reading the brief opinion piece by Jessica Wakeman to find out what people are upset about. Here’s a snippet: “Some folks on Twitter are upset that in Gaelic, the name Kieran means ‘black,’ ‘little dark one,’ or ‘dark skinned.’” However, reading between the lines of Wakeman’s article in “Frisky” magazine, it’s likely that the kind of people who are uncomfortable with an African-American president are also uncomfortable that a member of the extended Romney family has adopted a non-Caucasian baby.
Wikipedia’s article about the Irish population mentions “black Irish” as a historical term that most commonly refers to people with dark hair (who may have fair skin and blue eyes or, less commonly, brown eyes and a Mediterranean complexion). It’s not clear whether dark-haired Irishmen resulted from remnants of the defeated Spanish Armada or from Spanish and Portuguese traders who populated Ireland with some dark-haired descendants.
Kieran is certainly an appropriate name for a boy with dark hair (and a darker complexion than most Irishmen). Similarly, Jennifer and Blanche are appropriate choices for girls with blonde hair and “fair” complexions; and Russell is an appropriate choice for a red-haired boy. (That’s why it makes sense to make the final name choice after the baby has been born.)
The whole “controversy” looks to me like a “tempest in a tea pot,” if you get my drift.