You could argue that HN is similar, where the highest comments are often the most contrarian. Which isn't to say they're not always valid, but I think it's important to be aware of this pattern.
Either we agree and elaborate, or disagree and eloborate (which is hard when you simply don't have additional knowledge). If we just agree, we upvote, because there is nothing to say, right? So that itself shifts the "pattern" some more.
I remember it also being like that in the small forums I remember fondly. We didn't have upvotes, but I still noticed that agreement is shorter than disagreement. But that was fine, since we kept talking through the months and years, we actually learned a lot. The flamewars very never so bad because we were few and close enough to be able to not "stop" them, but simply throw all fuel into the fire right away, and then cleared out the air after it was all burned. I remember a guy thanking us when he finally got around to not being a bit of a racist anymore.. We ribbed on him occasionally for several years, but never in a mean way, and he ended up writing us a thank you letter style post. I forgot all the details, but I'll never forget that actually happened. Still proud of that guy whatever the nick was ^^ That really can only happen in small, long-term communities, I think. Maybe it's simply not possible to "scale" that indefinitely, because it's about human capacity.
Whoops sorry, I only just saw I messed it up a bit (other than "eloborate" :D), but can't edit it anymore, I meant to write:
> either we agree and elaborate (which is hard when you simply don't have additional knowledge)
meaning in that case we can only upvote, i.e. just agree and don't elaborate. I more often find myself agreeing with comments than in a position to add anything to them.
I had a conversation in a forum recently about something like this. This particular forum has a kind of upvoting system but no downvoting system. Occasionally there's threads asking to put in a downvote system or asking why there isn't one.
The general consensus tends to be that it's easy to just agree with something but if you disagree with a topic or post it encourages better conversation to have to explain your stance and why you disagree.
I've posted on those forums for a long time and generally i notice this is what tends to happen more as opposed to a place like reddit, or even here sometimes, where a post just gets downvoted away with no counterpoints or discussions.