I suspect that when one blocks one of their friends on Facebook, Facebook systematically reorders the friends who appear in one's profile in one's 'Friends' pane. I'm sure there is a purpose for it that has nothing to do with showing people who has been looking at their profile, but that appears to be a byproduct of their algorithm.
I suspect that immediately after blocking someone who is a 'friend' on Facebook, the friends who appear in the 'Friends' pane are people who've been looking at one's profile.