I did it a while back (3 or so years ago) by scrolling through the dialog so that all of my "friends" were loaded, and then opened up the browser console and wrote a line of JS to toggle the checkbox to delete each of them and saved.
Not sure if that's still the interface today, but it worked for me back then.
* Edit: I checked, and you can still do this. It's under the main preferences dropdown -> News Feed Preferences -> Unfollow people and groups to hide their posts
It's no longer a checbox, but you can simulate a click in JS. Haven't tested so obviously YMMV
Not sure if that's still the interface today, but it worked for me back then.
* Edit: I checked, and you can still do this. It's under the main preferences dropdown -> News Feed Preferences -> Unfollow people and groups to hide their posts
It's no longer a checbox, but you can simulate a click in JS. Haven't tested so obviously YMMV