Section 3 Unsportsmanlike Conduct
Article 1 There shall be no unsportsmanlike conduct. This applies to any act which is contrary to the
generally understood principles of sportsmanship. Such acts specifically include, among others:
a: Throwing a punch, or a forearm, or kicking at an opponent even though no contact is made.
b: The use of abusive, threatening, or insulting language or gestures to opponents, teammates, officials,
or representatives of the League.
Note 3: Violations of b: will be penalized if any of the acts are committed directly at an opponent. These acts
include but are not limited to: sack dances; home run swing; incredible hulk; spiking the ball; spinning the
ball; throwing or shoving the ball; pointing; pointing the ball; verbal taunting; military salute; standing over
an opponent (prolonged and with provocation); or dancing
I understand this part of it entirely, but that's not what I was questioning.
The two examples I cited, the sack dance and spiking the ball, are penalized even when not directed at an opposing player. Again, my guess is the league purposely gives the officials some leeway and count on their reasonableness.
In general, celebrations that do not show poor sportsmanship should be allowed. Cam getting penalized for going down on one knee after his first TD is an example of the league and/or officials going overboard.