That is why I like Subhumans.. they write overtly political music but try to make it more on vague societal themes rather then any particular political situation (mostly) and so the music ages a little better..
Songs like
Our Society or
Dying World remain pretty valid in 2014 as much as they were in 1984..
Within Bikini Kill, they addressed in their music the kinds of issues for women which are still relevant albeit in a different tone the was the 1990s.. If you took Bikini Kill lyrics and put them to some Warpaint you'd have the 2000s musical version and it'd still be like 99% relevant. But to concede your ultimate point, yes, 99% of the time (repeated this on purpose) political music is dated to a particular moment.