I'm pretty sure someone is immune to karma for the first few posts. (Ten, or so?) So someone can come in, make a few newbie mistakes, but clean up their act and quickly soar to Guru by being witty and conversational by post 100. It's happened to plenty of people.
Very few people actually bother with the "because I don't like you" for posters - hell, there are posters in the Asylum, in XI, and in other Cross site areas that I dislike intensively but have grudgingly rated up because they've made a good point. Systematically rating someone down, e.g. karma camping, is considered bad forum behavior and when suspected can be reported to a mod.
No, our current crop of trolls deserve every bit of bad karma they've earned. Just because they can't figure out why we're rating them down every post doesn't mean they deserve it any less.
The first time I ever joined an IRC chat channel, I was naive and asked them moderator of the first place I landed, "I heard you could download movies and stuff here?" Within a few minutes of an increasingly hostile conversation, I was kicked out of the channel. I didn't feel like I did anything wrong, but as it turns out the pure chat IRC places resented the download piracy places because they assumed they might eventually get IRC completely banned. (Fortunately for the fansub industry, Bittorent and Pirate Bay turned out to be easier targets. IRC is still where you go to find fansubbed anime you can't get anywhere else.)
No matter what forum ratings system is used, there will be people who just don't "get" the culture that the rest of the forum has built up, and will have trouble fitting in. The karma system at least empowers regular users to deal with bad behavior proactively instead of tattling to a mod any time someone says anything stupid.
____________________________FFXI: Catwho on Bismarck: Retired December 2014
FFXIV: Katarh Mest and Taprara Rara on Lamia Server - Member of The Swarm Curator of the XIV Wallpapers Tumblr
I can't understand anyone who skips the cutscenes of a Final Fantasy game. That's like going to Texas and not getting barbecue.
and the XIV Fashion Tumblr