No, he wasn’t “mistaken”, nor was he lying, nor did I accuse him of such.
It may be instructive to look at the actual exchange from the link below.
The poster made the statement “And Kantian ethics permits retroactive abortion up to age 13”.
I said “I want to see a credible cite for that.”
Poster acknowledges that he doesn’t have a cite, but alleges that it follows from Kantian ethics. I argue that it doesn’t. Clearly this is the poster’s own interpretation, hence my observation that he “just made it up”. Which he freely acknowledges in so many words: “I made it up but I think it follows from what Kant said.”
The upshot here is that we’ve established that his view is his own interpretation and not something that can be cited from authority. Yes, “you made it up” is a blunt and direct way of saying that, but in this context that is what it says, and nothing more. In a completely different context such a phrase could be used to imply that someone is lying, sure. But not here. That’s why, as always, context is important.
This specific incident was no big deal and I only bring it up now as an example supporting my earlier concerns about blanket prohibitions on specific phrases because of what they might mean. I’m trying to promote reasonable use of language here, not trying to a jerk advocating the use of gratuitous insults.
Like “you’re right”, “you’re wrong”, “you have a point”, “you misunderstand me”? That doesn’t seem like a very practical rule, or one conducive to natural conversation.