The first time he guarded Bynum, ever, Bynum scored on him. That's obviously the point where you completely stopped watching Splitter play, because everything that happened subsequent to that flies in the face of your conclusion.
Splitter went right down on the next possession and drew a foul on Bynum. Gasol came in for Odom and those two collectively scored one point while Splitter was on the floor after that.
The Dice tip-in game had Splitter defending Bynum in the post, and Bynum tried to throw his weight around. He was completely unsuccessful doing it. Splitter drew an offensive foul on him and he was very frustrated at Splitter's ability to keep him from his spots.
Collectively for Splitter against Bynum in those two games, Bynum scored three points, had two fouls, and the Lakers scored two points in the paint (Bynum's first basket). Not too shabby for a rookie that can't earn playing time ahead of Matt Bonner.