This is one of the many reasons why I replied "100% disagree" when you originally wrote "if someone writes a detailed reply, replying ‘no’ is rude." I wasn't even sure why you wrote that in the first place, since the other commenter you were referring to did nothing of the sort.
I'm happy that you agree that your assertion, as originally written, is false. I'd encourage you to think more about nuance before making blanket statements in the future.
> I didn't agree that any assertion I have made was false
Yes, you did, implicitly, by adding additional qualifications to your original assertion: that it’s ok to reply “no” when the person may have written a detailed reply but you just want to answer a question asked in the post (and ignore the rest of the post).
There are many other similar situations where I would likely agree with you that replying “no” is OK and not rude. I hope this clarifies things.
I'm happy that you agree that your assertion, as originally written, is false. I'd encourage you to think more about nuance before making blanket statements in the future.