But that seems illogical. First, he has played in crunch time. Second, playing a bit less in crunch time doesn't necessarily have anything to do with offense. It seems much more likely to do with not wanting a foul at a bad time.
Teams don't compromise their defense just because the crowd "buzzes." If the crowd buzzed because Shavlik Randolph got the ball, the defense wouldn't double team him. Bad offensive big men don't draw double teams in the post. Double teaming incurs a significant cost...you only have three defenders for the other four guys. Which has led to lots of open shots. The result is that Portland has one of the most efficient offenses in the league (in the top three according to Hollinger, Basketball-Reference's Offensive Rating and Basketball Prospectus' team offense rankings). It's hurting opposing defenses to give up open shots, and yet they keep double-teaming Oden.
All due to crowd buzz?

Doubtful, IMO. I think it's much more likely that they don't think a single defender can keep Oden away from the basket, but Oden hasn't yet figured out how to score against two defenders.