As the editorial mentions, some reviewers will attempt to guess the identity of the authors. There will be clues in the paper, no matter how careful the author is. A few reviewers will be certain they have guessed correctly (even though they likely will be flat wrong). To what extent this guessing will influence the review, is not clear. Hopefully, most reviewers will simply shrug and focus on the paper's content, which is what they should be doing anyway.
Coincidentally, I just completed a double-blind review (my first) a few days ago for a different journal. Interestingly, the journal did not explain that the paper's authors would not be revealed to me. Instead, I was provided the usual links to the paper, which contained no mention of the authors or their affiliation. Not finding that information anywhere, I finally realized that this was a double-blind review.
Did not knowing the author's identity affect how I conducted the review? Not really. In fact, I liked not knowing who the author was quite a bit more than I expected. I wonder if other reviewers will feel the same way?