Depends on your definition of "new". This was not nearly as common 20-30 years ago because there was stronger belief in "sportsmanship" where gloating and demonstrating was frowned upon to some extent. That ethic has been deteriorating over time, and Adrian W. just pointed out that we're kind of at the low point. Assuming you value such things.
And regardless of how recent the phenomenon is, I agree with his point that it is particularly obnoxious in this context given the size difference between Jordan and Knight. So a 6'11', 265 guy dunks over and knocks to the floor a guy who is 6'3" and only 190, who had the guts to take a charge. Impressive, especially when some say Knight should just quit basketball, etc..