Why didn't you upvote any of these? Your screenshots show comments for which you haven't yet voted. The first two (as of right now) are currently sitting at zero, and with your upvotes they would be fairly sitting at one.

I think that we can agree that the larger the community, the more likely that we'll see random downvotes. However, any unfairly-downvoted comments will generally be fixed by the rest of the community over time. The question is whether the comment scores fairly represent the comment in the long-term. I think that a score of 1 is fair for the first two, and if you had upvoted, that's where they would be.

I don't think there's currently a downvoting issue; the community is handling it quite well, and unfair votes are corrected quickly. There are some edge cases where some comments with a low number of views (such as those in a story with few votes, or in a story with a large number of comments) might unfairly get stuck at 0 or -1, but it's somewhat rare. If 1-2% of comments are unfairly sitting at zero or -1, I don't think it's a big deal.

I disagree with you about the 3rd comment. The last pair of sentences is pure flamebait, which is why it's being downvoted.