What's so bad about them booing him? Right or wrong, people are paying to see a certain caliber of performance, and if they don't see the performance they are expecting, they will be unhappy and express that displeasure. I guess I'm more "intimate" with this concept becuase I act and I would expect the same response if I got up on stage in front of a crowd of guests and blew 90% of my lines. There's more than basketball at stake here - there's a show to put on. That's why the fans pay the bigs bucks, and that's why you rake in the millions.
Or maybe it's just because I'm from Philly, and when someone does a crappy job, particularly a sports star, we don't coddle them.