I daresay they could get away with it for the same reason that a lot of DS9 viewers forget Sid's background. ...Or choose to see him as white.
It wasn't until he mentioned it in DS9's special features that I ever gave a thought to Sid's skin color. Even with the foreign sounding name, I never thought of him as being any particular ethnicity. Not once. Maybe part of that is because he's about as dark skinned as my dad, whose ethnic background has honestly always been a bit of a mystery to me, but considers himself white, and as far as I know, has seldom been regarded or treated as anything but.