I'm guessing he's referring to the beam. Like a car headlight is shaped to avoid blinding onlookers by "cutting off" just below the height of the other guys windshield.
I thought that was the whole point of the "city mode". It uses only the lower LED and is hooded by the body of the light. Then, when you need to see something out front you hit the remote switch just for a second.
For my purposes, if I'm riding in traffic there's usually enough ambient light that I'm not running on full output anyway. I've only got it cranked up if I'm on my mountain bike on the trail in which case I'm not blinding anyone.
It's also possible I completely misunderstood the comment.