I thought it was odd, too.
I believe the user was implying that cylindrical waves, *for some geometric reason*, did not propagate “sharply”, because Huygens wavelets - outside of the new wavefront - wouldn’t completely cancel each other, leaving a “wake” behind the wavefront.
I always assume to know less around here, and the information was from a rather prominent user, so that’s why I questioned. Thank you for the attention, though, very glad for the feedback!