That consideration is baked into my post. They fall under category 1 as well.
To put it another way: you say that people who are merely politely disagreeing are in your category 1, but you also believe there is a problem on HN with "loud trolls" dressing up their comments to appear civil. That's counter to my experience here. YMMV etc of course.
Right now i'm thinking that your bias in perception is that you tend to look mostly at technical topics where there is no opportunity for this kind of rift without going obviously off-topic. (What your perception of HN is is highly determined by which comment threads you look at.)