My experience with standards of politeness in fandom is that they are often understood to allow the fewest possible number of speakers and promote behavioral conformity.

I've also had read some arguments (none of which I can find at the moment), which persuasively make the argument that the promulgation of some sorts of free licenses (specifically, CC) which explicitly permit activities which are legal regardless (specifically, transformative work making commentary on the original), puts a negative pressure on the actions when taken towards those works for which the action would still be legal, but no explicit license has been given.