You're comparing two things that are actually quite different. In your example, the other person thinks that you are being honest, and is mistakenly trying to help you overcome your unlikely sequence of obstacles. In the example you're comparing it to, they are trying to confuse you out of your principles by showing off their verbal skills. Here is an example that I think gets at what you're going for:

"Quit making fun of me for my big nose."

"Hey, that's a legitimate form of humor dating back to the third century BC, when Prodigious wrote..."

"That doesn't have anything to do with my feelings, could you just stop?"

"Facts don't care about your feelings."

And so on...

>Giving a justification is seen by these people are an excuse to debate.

I know what you mean here, but I disagree that my suggestion opens up a debate. It is clear what about the action in question was, and it politely asks not to do it again. Debate cannot exist one sided, so if the person is intent on "debating" a simple, "we can take this offline later", or "its not up for discussion" usually clears things up. Just because someone wants to debate, does not mean that you need to engage them.

Regarding your scenario, if person B simply just said "No" it would eliminate all of the need for future questions. This isn't the same thing, as person A didn't violate any social agreed upon rules by asking their question.

> Debate cannot exist one sided, so if the person is intent on "debating" a simple, "we can take this offline later", or "its not up for discussion" usually clears things up.

Perhaps you could try the phrase "we don't do that here"

This was a follow up to the original transgression, you have to be clear of what you are shutting down, before you shut it down. Again the two statements I said are much clearer and don't single out the recipient.

"It is hurtful when you do X" doesn't single out the recipient?

It does not single them out in opposition to the group. Say "we don't do that here" puts the transgressor on one side and the "we" on the other side. Saying "when you do" is not putting the transgressor on a side, but rather placing the onus on them.

My statements don't put the transgressor in opposition to the group, is what I should have said. But I think that thats actually the intention of this author and I don't agree with it.

> Giving a justification is seen by these people are an excuse to debate.

Yes. This is a bit tautological because 'justification' is a word that connotes normativity, perhaps unlike 'explain' or 'describe'... but justifying yourself to someone else effectively invites them to negotiate your decision because it's a tacit admission that it matters (to you, or perhaps according to a shared social norm) that your decision is one they'd approve of in some sense.

However:

> For another example, trying to turn down something you don't want to do:

> A: "Can you come over and fix my Wi-Fi?" B: "No, my car's in the shop" A: "Oh, that's OK, I can give you a ride" B: "No, I have to go get dinner" A: "Oh, that's OK, I can feed you"

Trying to address someone's express concerns is not debating them. Don't tell somebody a fake story about what you want or why and then get upset when they honor your words!