Divisive political topics are usually flagged heavily, especially when they have little connection to any novel subject of intellectual interest.
HN is not, and does not seek to be, a discussion board where the subjects are driven by simply current general interest salience, and just because a topic isimportant doesn't mean it is particularly relevant for HN.
There's lots of discussion fora in the world, HN doesn't have to cover all the space.
From the guidelines:
Off-Topic: Most stories about politics, or crime, or sports, or celebrities, unless they're evidence of some interesting new phenomenon. Videos of pratfalls or disasters, or cute animal pictures. If they'd cover it on TV news, it's probably off-topic.
Maybe thats why ?