I think one of the problems (and it is not just localized to HN) is people mistake the downvote for, "I don't agree with you". I get downvoted all the time for my position on full client side browser apps. Which to me is the silliest thing to downvote someone for and it seem to be the big one. Not my position in general, but technical dogma in general. It is a form of group think and I think at a certain level it is inescapable.
For example, guy (A) like Apple guy (b) does not. Each provide their reasons and both are valid points as to why each holds their position, but many times that exchange will result in a third party that agrees with one downvoting the other. I don't understand why people equate "i don't agree" with "I need to downvote" but it happens and it leads to group think.
Given that, similar post receive higher scores while opposing views get suppressed, by the would be poster out of fear of reprisal or from downvoting. There are some key ones that are pretty common obviously Apple is a big one. NoSQL vs Relational is another. Anyway, this does make individuals second guess expressing there real opinion on a subject for fear of being downvoted.
If a system could be designed to identify someones bias and make the weight of their down votes and up votes count less for items they show a bias for, I think you could kill some of the group think and fear of reprisal. Also I think downvotes from a users page should be track with particular interest. I do not think it is rampent but I have seen instances where one user is targeting another user with downvotes by visiting their profile and downvoting their threads. I had it happen to me on two occasions one of them I pinpointed who it was because only the posts that the user had not replied to me had been downvoted, given that you can not downvote a post you replied to it was pretty obvious who had done it. Anyway, I think there are some ways that a system could be built to identify downmoderation abuse and weaken or remove those privileges.
For myself personally, I say what I think if it gets downvotes then so be it. If I get downvoted to oblivion guess what? The community just validated that it is not the right community for me and it is time to move on. Either there is too much group think or I just have nothing valuable to provide to that community, either way why would I want to hang around. So far most of you guys like me and I am thankful for that as I like HN and yes my real info is my profile and my user name is my initials.