I have no idea why you are italicizing types of logical fallacies. I can't think of a good reason to do that.
And just pointing out that you believe they are committing a logical fallacy without any explanation is a very lazy discussion technique.
And just pointing out that you believe they are committing a logical fallacy without any explanation is a very lazy discussion technique.
If I were to guess, it is because it it is a term from a foreign language, in this case Latin, not because it is the name of a logical fallacy.
There exists an orthographic, or perhaps typographic practice in English to italicize words and phrases borrowed from other languages, like à la carte, du jour, sine qua non, ...
As for your second point, I think it's pretty clear from both my comments and their context why I'm pointing out those fallacies. That said, in the case of "non sequitur", I was actually referring more to the literary sense of the term — "Where the hell did that come from?" — than the fallacious "does not follow" sense.
When you respond twice in a row in a comment chain saying that they are using a logical fallacy, and nothing else, you've done nothing to add to the conversation, but are playing the role of Logic Studies 101 Professor. That's probably what they meant by the looking back on on your writing comment.