Context While Modding

To me, it’s an obvious insult when someone insults a person. What makes an insult obvious to you?

Here’s some context from that thread:

That looks like sarcasm directed at the same poster to me. The post that is in the OP comes after that. That makes the comment look more like an insult to me.

What would that change look like? How would you define that line?

So far, I’m not following how you would know which insults are obvious.