That's weird, I was just talking about this yesterday to a friend that's seen the fight (I never have).
I'd heard conflicting reports, some saying Holmes deserved it and others saying Nielsen.
My friend felt that Holmes should've definitely got the nod.
But he pointed out that Holmes should've lost to Mo Harris and had a tight one against Quinn Naverre that year too, so swings and roundabouts I guess...Holmes had his fair share of tight decision in favour as well as against.
I've always felt the same way about Holmes vs Spinks.
First fight was close but I always felt Spinks deserved the nod. Second fight, no way.