Simple... because Irish phonetics are not known to most of the rest of the world, and the sound of the letters makes no sense to an outsider.
Aoife is only just becoming well known in that States, and still people would have trouble spelling it here. The same way that some people still pronounce
Jose with a hard j instead of (what we call) and "h" sound.
Foreign pronunciation leads to mispronunciation.
It's nothing to be insulted about. It's to be expected.
Ex... my husband is named
Julius (which is even more common than
Aoife in terms of multinationality). People say yoo-lee-us, jool-ee-us, hool-ee-us, yoo-lus, Julis and jew-lees. Simply because people use the phonetics of their native language to sound out names at first glance.