Poopy butts are very common, so when I read your post I also thought it was on the butt--then I looked at the photo, and realized your chick had poop on the other end instead :lol:
Wiping its butt makes sense.
If so much poop gets stuck that the butt is completely covered and the chick can not poop, then it is a real problem.
Small amounts of stuck poop are not directly a problem, but it's usually a good idea to keep it cleaned up so it does not become a big amount of poop.
If you use water to wash off the poop, then the chick is wet, and then it gets cold.
If that happened, you could put it under a heat lamp while it dries.
(I think that's what's being suggested, although since I'm not the one who made the suggestions, I might be wrong.)
Edit: forgot to mention...