If you're saying that there are people in this thread who "can't handle" "gg" in the sense of mental illness, I disagree. There are people here who find it rude and don't like it, which is hardly the same thing. One does not simply cater to people who find your behavior unpleasant.
Care to support your assertion? Not a single person, ever has a mental pathology that causes him to behave with unsportsmanlike conduct?
So I'm re-reading SCSN's post with a slightly different eye. He writes about people who "can't handle it" and are "maladjusted" - I picked the former phrase out of your post which was probably a bit unfair of me. These terms do sometimes describe mental illness, but I think he's just referring to "ordinary distress" rather than mental illness.
I basically agree with his sentiment that if you're upset at me for trying to be polite (as in this case, by saying "gg"), well, I can't really be expected to know that in advance or avoid the politeness in general.* Certainly no one in this thread looks ill to my untrained eye, and while I've seen some childish behavior on Goko (and Iso), but this is
certainly not the kind of thing that warrants special treatment.
Put another way, I don't see why a relatively rare preference against "gg" counts more than a more common preference for it. Harm is done to the group as whole when simple politeness is made testy, but that harm may be outweighed by disproportionate harm done to the rarer dislikers. I don't see evidence of this.
There are many cases where one caters to the person who finds your behavior unpleasant or one is an asshole. For example, if you're writing a blog post, there are certain topics where it is appropriate to put "trigger warning" because a large fraction of people is going to be especially sensitive and insensitivity to their needs is gross negligence. A legitimate disagreement about what's appropriate doesn't seem to one of those cases.
*Intention of politeness is not a magic balm that excuses any behavior, but in this case, the "gg" convention seems like a generally positive thing. I could be swayed from this position, fwiw, but arguments I have seen have not been convincing.