That's also an important distinction. When someone is so wrapped up in an idea, or more accurately, an opinion, then pointing out very real flaws seems to them, to be pointing out their flaws. Which if they want to take it like that,points out different, but very real flaws in them, so in a way it's true - just more of an own goal then a point made by the opposition.
It doesn't always work, but any internet debate works better with a float like a butterfly, sting like a bee approach. Accept valid criticisms and points made, have your own solid and reliable. Moment you get emotionally invested, and start punishing the poor keyboard with VERY. STRONGLY. TYPED. WORDS. you're making a spectacle of y'self, and becoming the topic, instead of the original points. And, it takes a lot of discipline to not prod sore spots with the stick of mild mockery, when the flailing is amusing.
Anyway, the thing I've found works worst, is long posts. It's not an inditement, but most arguments and points can and should be succinct and an easy progression to follow. A long post either won't be read, or someone who is looking to start shit will find the one sentence that's poorly worded, spin it and claim that this renders everything else invalid. Which is purest bullshit, but shifts the momentum, and turns it into dull quibbling.
Worst worst, is poor use of paragraphs (or, not) and other grammar tools to space out the text.