Arguing about almost anything is a favorite pastime of technical communities everywhere. Some folks seem to treat it as blood sport, some have no intention of hurting others but manage to do it anyway. A great deal of the time people are not arguing to convince, they are arguing to confirm their existing belief, a form of axe-grinding. Many really great people are chased away by a lack of grace and respect in a community's discourse. It needn't be that way. Here is a heuristic approach to arguing in a way that not only mitigates the problem, but improves the outcome for all concerned.
Assume:
Find the parts you agree with. Be honest, do not argue against things with which you would agree if they were said by someone else. Do not argue against things on the basis of dogma ("never do this", "always do this"). Dogmatic, rule-based arguments may well be dishonest ones. Exceptions to rules always exist.
State, in your own words, what the person is trying to say. Do it sympathetically. That is, try to state it in the most convincing and effective way, as if it was your own argument, and you agree with it completely.
Before you begin to deconstruct the person's argument, give them a chance to fill in the gaps. If you assume what they will answer to the objections and move forward, you are not only ignoring salient information (what they will say) but also their independent humanity.
Ask them to clarify points that seem to lead to a nullification of the argument. Ask, sincerely, that is, assume that you misunderstood, or that they failed to include important details. Avoid rhetorical tricks designed to obviate the need to actually deal with what the person is saying. Doing this is actually a form of arguing, but it can lead to your agreement instead.
Don't adopt the attitude of your own infallibility. Disagreeing is perfectly OK, but keep foremost in your mind that you might be wrong.
Iterate these steps until your discussion is done. Be prepared to actually change your mind. Be prepared to accept arguments that are counter to your opinions, or call into question dogmatically held beliefs. Be honest, be brave enough to say, "I was wrong" and be made better by your interaction with others.