The best advice has already been put forth - if there are two interpretations of what someone said, and one pisses you off, pick the other one.
Of course, that's easier said than done. And, also of course, prior posting habits can cloud the issue as well. If someone (SHOCK HORROR) changes their mind, that can be really hard to communicate on the Internet particularly when people start dragging in prior conversations.
And, this can get taken to extremes where a simple off hand comment sparks ten pages of rebuttal with people dredging up quotes from other off hand comments made years before.
On the other hand, if someone has a history of posting a certain way, and the current discussion isn't really different than those other ones, it's pretty hard to take their point in any other direction. Several people in the "Disociated Mechanics" thread tried saying that we should view The Alexandrian essay in a more positive light. But, that ignores a rather lengthy history of TA pretty much constantly, and quite agressively, criticising 4th Edition.
For myself, it certainly makes viewing that essay as anything other than yet another edition war salvo problematic.
But, in any case, trying (and try being the operative word here) to read other people's posts in a positive light and, again trying, to avoid directly combatative language is always good advice.
Now, if I could only FOLLOW my own advice.

Then again, I've found that the Ignore function on En World makes a world of difference. There are just some people I cannot have a rational discussion with - it will always turn into a morass of asshatery (and I certainly don't blame them for that, I'm a more than willing participant) - so simply refusing to engage has made things much easier.