Hacker news is a news aggregation medium for "Hacker News." The purpose of this site is to get your fix of tech news that you can't get other places. It isn't burying your head in the sand to ONLY have "Hacker" news on your Hacker News site. It's sticking your head in the sand not to read any other news sources. That is on the individual. It is not the job of Hacker News to educate you on politics. The responsibility of getting good news is on the user not the medium. HN doesn't claim to be a one stop shop for all of your news.
More importantly, this is an experiment, on a site that is very interested in Science and Programming. It completely makes sense to have an experiment like this to see if it affects the quality of the comments. Being against this experiment is like my dad trying to tell me that God Created the earth 5000 years ago from parts of other planets (complete hyperbole). WTH? It doesn't matter it's one week and then it's over.
I'm assuming a good experiment will THEN make assertions and consult with the community to see if this worked, was bad/good/etc. At that point voice your concerns, but not yet, there is no evidence it's all conjecture.
I'm not sure yet whether I think this is a good or bad idea, though this I'll say: HN is not just a news aggregation medium. If in the beginning it were, it is no longer. It is now much more defined by the people on here. Like reddit, the story pages give the majority of screen real estate to comments. It's not a stretch to say people on here drop by, to a greater extent, for the discussions, ideas, and tips - and to a lesser extent, to be exposed to a story or link that they might not have eventually found elsewhere.