It is also about name length and hyphenation. I have often seen athletes with long and hyphenated last names be shortened with initials, especially on message boards where people post rather quickly and posts might have autocorrect lingering underneath. Is "hard to spell" correlated with non-Anglo names? Sure. It is only natural to have more difficulty with names that you are less familiar with. I am dreading trying to spell the Caps new 1st round pick (Ivan Miroshnichenko) on message boards. I also double check whether I get the "Ps" and "Ls" right in Mark Appel's name.
I also am pretty sure that Mr. Pouaka-Grego would be thrilled to know that posters in Philadelphia, Washington, Austin, Oregon, and even Ireland are noticing him.