I've always looked at internet conversations as gentleman's agreements in politeness and respect. What I mean by this is that any given internet comment can be a hate filled flexbox of bile and swear words, but most aren't, because that would be a violation of the agreement. But once the agreement is broken (or one of the tiers of the agreement is broken) then no subsequent discussion is beholden to that level.
So in this example, you broke the tier of "blunt criticism". Now that the tier is broken, all responses to your comment are not beholden to that implied agreement. And rightfully so, one of the comments bluntly tells you that you're the one with the issue. Then you said this was completely uncalled for even though a) you started being blunt and b) their response was less rude than yours.
So in summary. Don't dish it if you can't take it.
"Horribly written" is blunt criticism, like it or not. The parent post is saying that because you delivered blunt criticism, you should be prepared to take it too.
If you actually read what I wrote I said "This seems to be horribly written." Note the word "seems" that is not the same thing as saying "it is." I then go on to ask a question for clarification which some folks were kind of enough to point out helpful and corrected interpretations. Asking a question and admitting something wasn't making sense to you are not at all the same thing as "dishing out criticism."
I specifically meant the post I replied to (where I'd agree, just that piece would be ambiguous. The full one as quoted in your initial post is not, because the part I highlighted clarifies the meaning)
My reading comprehension is just fine, the following statement is full of ambiguity:
"subset S containing k (k > 6)"
A more articulate way to express that would be "subset S that contain k elements where k is greater than 6"