I don't know if the comment was edited or not, but I hope you're not claiming "vigilante" is a slur. I looked up the definition of slur just to be sure and you are technically correct, but I'd say you're abusing language far more than the person you're responding to.
Editing a comment after the fact in a way that deprives a reply of its original context and makes it look stupid is, in most cases, a dick move. I think most users understand that. It doesn't make a difference whether the reply was by a moderator or not.
- Getting snarky because they did the reasonable thing and got rid of the slur after it was pointed out
- Calling said user a dick. If Karen is a misogynistic slur, How is dick not moreso misandristic? I realize you said "dick move", but that's functionally the same. Saying something was a "c?nt move" or a "n????r move" would be tantamount to calling someone a c?nt or n????r.
- Because maybe it made your comment "look stupid"
Jawdropping desecration of the guidelines. You need a vacation.
In most of the spaces I frequent, an edit to change objectionable wording after being called on it is acceptable. Since you've made it plain that that sort of approach doesn't work here, I'll keep that in mind.