The rule says "sarcastic GLWS comments". If it can be construed as sarcastic, it's treated as such.
It's a judgement call. If we perceive it as sarcasm though, somebody else likely would too.
Based on your comment, GLWS is not banned, but it is not to be used sarcastically. THAT has been the case for a number of years, maybe 4, I don't know. It sounded like if GLWS was used at all, one would get a warning. VHinch, make a note of this, because you don't hear it from me often, "Thank you for your reply and clarification".