How strict is this? No discussion of piracy, for instance? Or moose walking on their front feet across roads? Obeying all laws in all the various countries the forum's users come from is impossible as one can't say for sure what's legal/illegal in various countries. Even if you know them all, it's nigh impossible to avoid. Discussion/debate on things like copyright, piracy, narcotics and so on... it's a common thing for almost any fora involving adults.
I have to admit, I don't truly understand this rule, nor whether it's strictly enforced or not.