I downvoted this post because I don't want to see more attention to politics here. I don't see it as an "accepted exception" but as a recent push for more political discussions.
It can be interesting to talk about social issues, but doing this under the explicit heading "politics" header is likely to prime people into paying more attention to the political implications of the topic.
I take the debates that have occurred in these topics so far as evidence that LWers are capable of following the disclaimer. As such, unless it starts bleeding over into other topics, it seems okay. I prefer having a contained place with a disclaimer than to let arguments start getting political in other threads and either derail the thread or get cut off even though an interesting point was being made.
As Multiheaded added, "Personal is Political" stuff like gender relations, etc also may belong here.