There is an unwritten code amongst professional footballers, and that kind of showboating goes against it. See germany v brazil 7-1...
While I agree that players may get vexed when guys show off, there are moments in football that stick in your memory because of the flair, ingenuity and sheer nerve of the player. Some of these moments may be deemed as skillful rather than showing off, but that would depend on the individual observer. Higuita's scorpian kick against England being an example of completely unnecessary showmanship, yet it has been voted as one of sports 100 greatest moments.
Maybe some players think it breaks their unwritten code, but I would like to continue to see these occasional moments in football.