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.

"subset S containing k (k > 6) of these 49 numbers", don't cut something important out of the statement and then argue it is "full of ambiguity".