Perfectly fine? Maybe you only watch videos in an extremely narrow group, which typically have only the most eloquent and empathetic commenters, but I think most people would argue that comments have been the worse part of Youtube since their inception.
Spam, trolls, racists, and flamers were routinely "thumbed up" in comments. And then we have the comments consisting entirely of "exact quote from the video you just watched" which typically have hundreds of thumbs up as well, and add absolutely nothing to any discussion on the video itself. I don't think I'm alone in saying the SNR of Youtube comments was low to the point that I never sought out to read them any more. And when I did, it was more of a "lets see how bad the train-wreck is" mentality.
There's two kinds of videos I watch. The first ones are ones I find on the internet, usually immensely popular. I ignore comments on these.
The second are videos from my friends, or select channels I subscribe to. These usually have a small viewer base (<10000 views), and in the comments one can actually have a useful discussion.
Of course now many of these small feeds say 'Comments are disabled for this video'. I assume it's because the channel owner does not want to link their google+ account, or some technical fuckup - it seems unlikely they'd all change their settings, but I guess it's possible.
Comments generally get disabled because people were Saying Mean Things. Next time you see that, look at how many likes/dislikes the video has--odds are it may have a lot of dislikes. Or the owner could just be taking a stand against the terribleness of Youtube comments by not allowing any.
No, I can't see comments on old videos that I'm 90% sure had comments before. Though it seems it's only on a couple channels, so maybe they have retroactively disabled comments on all their videos.
I'm not sure what people are expecting. YouTube is a site that has a wide, general audience that includes adults and children, of all backgrounds and nationalities. The popular videos are almost exclusively lowest common denominator pop crap or viral trends. I wouldn't expect anything resembling actual discussion on the latest Miley Cyrus video. You can't even get that from HN or reddit. People seem to forget the Usenet days, where a conversation could last weeks or even months. YouTube, HN, and reddit are all hit-and-run sites.
Damn, you just made me incredibly nostalgic. Not only for Usenet, but for things like Fidonet.
Not that Usenet didn't (and still does) have its problems, but I feel you're right about the quality of the discourse in some of my old favorites. However, I've personally always attributed that to the higher barrier of entry than the medium itself. See: "the September that never ended".
Spam, trolls, racists, and flamers were routinely "thumbed up" in comments. And then we have the comments consisting entirely of "exact quote from the video you just watched" which typically have hundreds of thumbs up as well, and add absolutely nothing to any discussion on the video itself. I don't think I'm alone in saying the SNR of Youtube comments was low to the point that I never sought out to read them any more. And when I did, it was more of a "lets see how bad the train-wreck is" mentality.