Okay, so, ad hominem is the name of a logic fallacy where, instead of arguing about the topic, a person will attack the other person in the argument.
Ad hominem (Latin for "to the man" or "to the person"), short for argumentum ad hominem, is a fallacious argumentative strategy whereby genuine discussion of the topic at hand is avoided by instead attacking the character, motive, or other attribute of the person making the argument, or persons associated with the argument, rather than attacking the substance of the argument itself.
I've seen this argument done before, usually against other people, but it's been a while since I've had it done to me.
Which makes me find it FASCINATING that it was attempted.
The conversation went like this:
Me: "Your link emoji causes your links to show up in the discover/books stream. Is this intentional?"
Him: "[Yes, intentional.] This particular one is highlighting a recent workshop report that was just released on Complex Systems Research. Though maybe not your cup of tea if you're into the fantasy genre?"
Now, I'm arguing that his post, which was tagged with a bookmark emoji, doesn't belong in a stream of posts that are book-specific. He admits it doesn't by saying it's a report, but, eh, maybe it could be if the report is in book form. But what he's arguing is that because I read scifi/fantasy books, I don't know what a book is.
Because... I read science-fiction/fantasy.
COMPLETELY IRRELEVANT TO THE CONVERSATION.
It's like watching a train wreck in real time. You want to look away, and JUST CAN'T. I ignored the comment in the rest of the conversation, because, really, mansplaining logic to a man will probably create an enemy for life, but I did laugh at the ad-hominem. A real life example! Right there!