Newbies do not get "chastised" for posting one-liners, at least not right away.
My personal tactic is to first rate a one-liner with +1A (if the person is truly new, i.e., has just joined and have not been lurking for years already), and the rating comment politely suggests the newbie to read the forum rules before posting, and points out that thanks, contact requests, and short comments should be done via rating.
People only get neg'ged after a few warnings, or if they have been members for a long time, and yet don't even bother to rate the OP, or read the whole thread, and instead they post a one-line reply asking for the wechat...
It has been pointed out earlier in this thread that the "no one liners" rule is buried deep among the guidelines. I checked and indeed found this to be true. I updated the
Forum Welcome, and it now has a short (yet prominently highlighted) paragraph regarding one-liners, or maybe we should call them NCSC (Non-Contributory Short Comments?)
Since the Newbies also tend to be puzzled about how RA works, I also added a table summarizing all the RA-related info (until now, there was a link which was pointing to an out-of-date table).
Feel free to have a look at the updated Forum Welcome, and if you have suggestions for other improvements to the guide, let us know.