I have seen it go over badly. I've also seen it go over very well. The running total so far seems to favor the latter.

I'm working mainly from Dale Carnegie. The core thesis is this: never tell someone that they're wrong. Instead, start by finding a way to tell them how right they are on a point you genuinely agree with. Once you've satisfied someone's ego, it becomes possible to engage with their intellect. This can be tricky, especially when someone's main point is something you disagree with.

I sincerely doubt that "What if all your stated assumptions are wrong?" would have been well-received. That's exactly the kind of comment that tends to get a defensive response rather a thoughtful one.

My apology was genuine. I had no reason to be nasty, mocking, or sarcastic to this person. I was hoping that they might be willing to re-examine their stated assumptions. I failed to sufficiently hedge against a sarcastic reading. Which is admittedly a difficult task in a text-based medium centered mainly around a language and culture that uses sarcasm heavily. I've yet to find a way to reliably do this.

I do appreciate your feedback. It's a work in progress.