gonvaled shared his interpretation of the context and his opinion whilst you are engaging in the personal attack.
I just wonder what would be Sarah's reply to your style above [dude, brain-mouth filter for trash talk...].
>> Sarah and I do not think ...
Are you Sarah's colleague, by the way?
umm, what? I didn't use any insults, I just talked about why the user's behaviour/arguments were bad. It's criticism, yes, but it's not ad hominem, it's on the behaviour and the ideas.
> "I just wonder what would be Sarah's reply to your style above"
If two (almost certainly) male people on the internet can't address one another as dude, I don't know what the world is coming to[1]. Some people might object, yes (I remember a particularly pompous twitter politico who balked at me calling him "dude" on twitter in an argument) - but this is how I talk out loud, and it's not obscene it's just informal. I don't believe it conflicts in any way with what I've said about being politely robust and emphatic.
> "Are you Sarah's colleague, by the way?"
no, never heard of her before this incident. I find it kind of sad that you thought I might be some kind of stooge. Feminist boys do exist, you know.
[1] I do occasionally use "dude" as an exclamation when talking to girls too, but it is usually in person and quite obviously sarcastic (I am British, and I say "dude" in a vaguely Californian accent, a result of listening to too much Blink 182 as a teenager I think.)