What do you mean 'hides' downvotes? You mean you aren't allowed to downvote, or that it doesn't tell you who downvoted you?
As for the former, downvoting is a privilege for those who earn it. The bar for insightfulness is deliberately high, and by putting it there, I believe the goal is to encourage everyone to strive for more meaningful commentary.
Looking through your comment history, it seems that you have some valuable opinions, otherwise I wouldn't be pointing any of this out. That said, it doesn't appear as though you put much effort in your posts either.
The hardest thing for me to learn about HN years ago was that it's often easier to just not say anything. I try to reserve my comments to where they either add value, or when my opinion was solicited. I'm not always able to avoid disagreement, but I try to always do so with respect and civility.
Simply put, it's a different place, and even though you shouldn't worry about, karma doesn't just drop in your lap. It's there to be earned. Earning karma takes effort. Effort in abiding the rules, effort in maintaining civility, effort in knowing whether your comment is worth posting or not.
HN is definitely not a groupthink, in my opinion, and some of the best chats on here are about arguments from high-profile users. In many of those arguments, there is resolution, where either one party has convinced the other that they are right, or they are able to come to terms with each others' opinions.
I think if you look at your comments in this thread honestly, with the criteria laid out here, you'll realize that they weren't exactly crafted with love. They aren't deserving of karma. Even if your opinion was unpopular, but presented well and thoughtfully, you'd see that you got karma in the process.
If anything though, karma is a long con. Don't worry about the karma on any given post, but try to keep the long-term average high.
Most people here desire the original article instead of a summary on Google+.
You are telling everyone they are wrong and pagerank knows better than them what they want. This isn't futhering a hivemind.