And has been largely irrelevant for the past 10 years. I still remember the day /. posted about some new web search service named Google. I was a big AltaVista user at the time and I remember trying out Google and thinking it was magic. Anyway, nowadays I come to HN to get my geek fix and pretty much leave /. alone.
Like, I'm guessing, many people here, I used to participate in Slashdot, but switched that finite collection of attention cycles to HN. I think the main reason was that moderation simply failed to bury the bad stuff and surface the good stuff, mainly due to moderator gullibility: commenters who wrote in an authoritative voice were routinely highly scored, even when insanely wrong. That and way too much simple immaturity, which, so far, seems to be successfully discouraged here.
You're describing a lot of what happens here with regards to scoring, just from a different perspective. Slashdot had actual discussions where it was acceptable to hold competing ideas and you didn't have to agree to disagree, unlike here. It's personal preference what sort of forum one likes.
I abandoned Slashdot after their horrible redesigning and forcing all users to use the ad laden pages.
commenters who wrote in an authoritative voice were routinely highly scored, even when insanely wrong
My favorite was the reverse psychology. Any post that began with: "I know I'll be downvoted for this ..." had a much higher than average chance of winding up at +5 Insightful.