Why can I see News Feed stories about someone who has yet to accept my friend request?

It's the last answer on the page.

A-ha! Thanks.

From initapplette's link:

Why can I see News Feed stories about someone who has yet to accept my friend request?
When you send a friend request to a person, public stories about them (stories that have the privacy set to "Everyone") may appear in your News Feed. This way you don’t have wait for them to respond to your friend request to see their public updates. Please note that News Feed will never show stories that a non-friend wouldn’t ordinarily be able to see. People who have yet to accept your friend requests will also appear on the Friends page. Here, you can add them to Friend Lists.

If you don’t want to see stories from a person who has yet to accept your friend requests, you can hide them from your News Feed by placing your cursor to the right of a story about them and clicking the "Hide" link that appears. Alternatively, you can remove them as a friend by clicking the "X" next to their name on the Friends page.

This is one of the things I dislike about Facebook: all too often, the blocking is set up one-way. I would like to control my own page's activity completely (insofar as anything online can be controlled); if someone is not my friend, I do not want my activity showing up in their feed, period. But Facebook only suggests ways for them to remove it, not for me to prevent it appearing.

That seems foolish at best. I am very, very restrictive about my Facebook usage, adding only people I know face-to-face. When I (inevitably) get requests from internet-only friends who use different parameters, I don't always deny the request immediately, and sometimes I completely forget to deny it. It never occurred to me that those people were still seeing my activity in their feeds: I intentionally chose only to show activity to Facebook Friends, and these people aren't Facebook Friends.

It's frustrating to realize that Facebook has once again sidestepped my carefully chosen preferences without warning.

Re-reading, I see

public stories about them (stories that have the privacy set to "Everyone") may appear in your News Feed

A-ha. So my rant was premature and pointless. Ooops.

And that is why you don't want me showing up in your Facebook feed: premature and pointless rants.