What is the possible was to be diplomatic and pragmatic when providing answers when there is a different view, different opinions or even contradict existing answers. Also in cases when you believe they are factually wrong. There are many schools a lineages which sometimes say different things. The Buddha also taught the same thing in different ways. Some options may be out of place but at least the poster thinks otherwise. Also is to OK to make reference to existing answers when adding your answer when you want to highlight different views and perhaps errors, though I think this might become problematic.
A general way to avoid being rude when you're talking with someone is to prefer to use an I-message.
For example if they say something which you don't agree with, then avoid saying,
'You' are wrong, what you said is contradicted by the fact that the Buddha said so-and-so
Instead prefer to talk about 'I' instead of 'You', for example,
'I' don't understand that answer, because my understanding is that the Buddha said so-and-so.
In this case (i.e. in answer to this meta-question) I suggest you concentrate more on what you are trying to say, and concentrate less on the fact that you're disagreeing with another answer.
When you write your own answer it's better if you're extra careful to say where your answer is coming from, to reference and quote it accurately.
For example an answer like the following has (or is) a reference and quotes,
The Manual of Abibhidhamma distinguishes Phassa and Phassahara. On page 103,
Phassa — Derived from √ phas, to contact.
For any sense-impression to occur, three things are essential—namely, consciousness, respective sense, and the object. For instance, one sees an object with the consciousness through the eye as its instrument.
When an object presents itself to the consciousness through one of the six senses there arises the mental state—contact. “It should not be understood that mere collision is contact”37 (Na saïgatimatto eva Phasso).
Like a pillar which acts as a strong support to the rest of the structure, even so is contact to the coexistent mental concomitants.
“Contact means ‘it touches’ (phusatã’ti). It has touching (phusana) as its salient characteristic (lakkhana), impact (saïghaññana) as its function (rasa), coinciding (of the physical basis, object and consciousness) as its manifestation (sannipàta paccupaññhàna), and the object which has entered the avenue (of awareness) as proximate cause (padaññhàna).”
Contact is mentioned first because it precedes all other mental states. “Touching by contact, consciousness experiences by feeling, perceives by perception, wills by volition—(Phassena phusitvà, vedanàya vediyati, sa¤¤àya sa¤jànàti, cetanàya ceteti).” According to PañiccaSamuppàda, too, Contact conditions Feeling. But strictly speaking, there is no reason for the sequence because all these mental states are coexistent. The Atthasàlinã states— “For of states, arisen in one conscious moment, it is not valid to say that ‘this’ arises first, ‘that’ afterwards. The reason is not because contact is a strong support. Contact is just mentioned first in the order of teaching, but it was also permissible to bring it in thus:— There are feeling and contact, perception and contact, volition and contact: there are consciousness and contact, feeling, perception, volition, initial application of mind. In the order of teaching, however, contact is mentioned first. Nor is the sequence of words among the remaining states of any special significance.” “Contact is given priority of place, as standing for the inception of the thought, and as the sine qua non of all the allied states, conditioning them much as the roof-tree of a storeyed house supports all the other combinations of material.”
(Mrs. Rhys Davids — Buddhist Psychology, p. 6.)
And on page 378,
âhàra, in this connection, is used in the sense of sustenance. Edible food (kabalãkàràhàra) sustains the material body. Phassàhàra or contact or sense-impact sustains the five kinds of feeling. By manosaücetanàhàra are meant the different kinds of volition present in the 29 types of moral and immoral mundane consciousness. They sustain or produce rebirth in the three spheres. Vi¤¤ànàhàra signifies the rebirth-consciousness that sustains the mental states and material phenomena (nàma-råpa) which arise simultaneously. There are such 19 types of rebirth-consciousness. In the case of mindless spheres they sustain only råpa; in the case of formless spheres they sustain only nàma. In the existences where the five Aggregates are present they sustain both mind and matter.
If you wanted to disagree with someone else's answer, which said that Passa should be avoided, your posting an answer like the above is almost sufficient: it doesn't contradict the other answer; but it instead it says what you want to say; and because there's an extensive quote the answer is both clear (well written, and already reviewed/edited) and authoritative (or at least, it's clear who the author is).
Another technique is to carefully limit your answer. You could start it with something like,
According to the Theravada, ...
According to S.N. Goenka, ...
When you start your answer like that, then you're not claiming that all Buddhists (all schools of Buddhism) would explain Dhamma in that way (so it's a kind of 'disclaimer)', but it also makes your claim stronger (e.g. you might not know what the Chan doctrine is and you don't want to argue with someone who's explaining Chan doctrine, but you do know what S.N. Goenka said so you're authoritative, sure of what you say, i.e. "thus have I heard", when you answer on that topic).
Also is to OK to make reference to existing answers when adding your answer when you want to highlight different views and perhaps errors, though I could imagine circumstance where it might become problematic.
I think you're right, that it is tempting to highlight the difference but that it could be problematic.
I can think of three things that would help to prevent it being a problem:
- The good-will of the other person -- if they're not likely to take offence, then any disagreement about the answers is less likely to escalate into conflict between the people; conversely if you think that the other user is likely to see your answer as some kind of attack, and to react with some kind of argument, then maybe the less said (about a direct and overt comparison between answers) the better, and just let readers see for themselves that there's more than one answer, and concentrate on making your own answer as good and clear as possible without criticizing (without even mentioning) another answer; alternatively if the other user doesn't have a reputation (in your mind) for being angry, then it's easier to
say that their answer is wrongsay that you don't understand their answer because it seems to be contradicted by something you quoted.
- The reason for the apparent difference is clear -- if it's obvious that the two answers are from two different schools then any difference between the answers doesn't have to be a difference between the two users posting, e.g. both posters can be more-or-less "right" and neither especially "wrong", if their answers are talking about two different things/doctrines
- Your attitude -- if you're angry and thinking, "that worthless, annoying, and presumptuous person is making mistakes again and being wrong in their answer, I'd better post another answer to correct them" then maybe the 'contrary' answer is enough and it's not helpful to highlight that it disagrees with another answers; conversely if you're thinking, "isn't it marvellous how true Dhamma is (or must be) expressed in so many different and even seemingly contradictory ways", and if you're saying, "look, his answer is pointing out the elephant's ears and here, this answer describes the elephant's legs", then that seems to me more helpful and less problematic.