I'm guessing that there are offtopic topics that can be categorised into "cute, interesting, fun, enjoyable, unlikely to cause harm or too much conflict" and there's offtopic as in "summon the shitstorms, let the combined hate of the Internet flow through you!".
While I would prefer less topics be 'taboo', I do understand the reasoning behind the choices, seeing as members have left over conflicts concerning those topics before. There are simply threads/topics which are pretty much sure to devolve and in the best of times nothing will get solved, in the worst case people will leave the forum due to hurtsee feelies.
I can see how a topic on cats vs. dogs will be fine, but a topic on the inferiority of XXX #1 to XXX #2, let alone XXX #3 will produce nothing of worth.
XXX being religion, political system, beer brand, football team