Burton's commentaries are all like that.
He's a man of many talents, but the gift of gab isn't one of them
Moderators are terrorists.

Edward Scissorhands is by far his worst commentary.

Are you Mr Burton?

I disagree I enjoyed Burton's commentary and didn't feel he interrupted Pee Wee at all. I also didn't find his voice annoying at all.

Why would he do it in the first place if it doesn't interest him?

Tim Burton also did the same in the 'Edward Scissorhands' commentary. You can tell by the monotonous tone in his voice, he is totally uninterested in what he's doing. And yes, Burton sounds like a dorky teenager, but I love his work nonetheless.
I've noticed he "Umm's" and "Err's" a fair bit which annoys me to some extent.
"Stop looking at the walls, look out the window." ~ Karl Pilkington On Art

This track was recorded shortly after Sleepy Hollow (a box office hit) had been released, so I don't know about him being un-cool at that point
but Burton has never been good at commentaries! The only one I would reccomend listening to is this one and that's all down to Reubens more than anything else.
"You average, typical, blocking the view of a God-damn, average, victim Bastard!"

The commentary was recorded when Tim Burton was no longer considered "cool", that ship sailed long ago, and so he's probably butt-hurt about it.