This is just being hindsight oriented. The way it worked out it was better to DRY from the start, but the person implementing it didn't know how the chips would fall.

If you do what this guy did and are wrong, it looks like yes obviously it was the same thing and you should have DRY right from the start.

If you DRY from the start and are wrong, someone writes a blog post about not DRYing from the start.

It's a bet on which mistake is worse, because you will be wrong sometimes. DRYing from the start IMO is a worse mistake than duplication.