Or they could just not show posts to groups you're not in and from pages and public profiles you don't follow! Allowing something to interject into your newsfeed should be opt-in, but right now it isn't even opt-out, except for not logging on at all. It would also be cool if there were a way to opt-out from seeing shared posts selectively for people on your friends list, e.g. I want to see things that Overly Political Relative posts themselves, but not things that they share from other places.
That being said, I deactivated my Facebook account a couple years ago, so I'm no longer a user whose opinion they should theoretically care about anymore.