The main reason I check out boards like this is to educate myself on the application of the rules. I'm certainly no expert, but at least I'm not the guy shouting "3 IN THE KEY" when the offense still has the ball in their backcourt.
In the defense of some fans, it is confusing when rules are enforced/interpreted differently by different officials. One of the common situations is A has ball and establishes frontcourt status. On a pass, B1 deflects ball into A's backcourt and one of A's players gains control in the backcourt. I've seen this called as a backcourt violation and also heard an official say "no violation, the ball was tipped". The casual fan has no way of knowing which call is correct.
That said, there is no excuse for beliigerent/unsportsmanlike behavior by any fan. I wish our league took a harder line on the issue.