There are times you need to delete a comment made to one of your articles.
And there are times, when the attack is so bad, so raw and evil that you 'win' the argument by approving it.
There are people who think they 'own' a topic or are 'defenders' of whomever you appear to attack; whether it's an oil industry, a dictator, a website, they feel empowered to launch blistering and often foul languaged campaigns against the writer.
Those who are young or new are taken aback, because the attacker often seems to be a 'senior' person who is 'well respected'.
(I am differing this attack from straight forward Trolling in which it is insult to insult, disrupt to disrupt and focusing on the slightly unhinged user who thinks he has some 'mandate' to insult/attack and the victim should just cower in the corner).
As no one knows anymore about you than your avatar (if you have one) and what you put (or don't put) into your profile, it is obvious no one knows who you are, really. They may know your purported 'stands' on the items you write about, but then, in many cases, you are being neutral. You have no stand. You are writing on a topic you believe people are interested in.
In some cases you've chosen a name which people assume is male/female or old/young and they attack that fantasy of you.
Many of the attacks are in all caps; this is excellent as anyone glancing at it knows that the writer is a few cents short a dollar. He starts as a raving mad man and the more obscenities and personal attacks he packs into his comment, the better it is.
Approve the comment.
Your only response to that comment is something like: "I have approved your comment so that the public can understand exactly who you are and how you behave." There is no reason to explain anything.
Using a commentor's own comment to gag them is the most powerful weapon.