Yeah, I get what you're saying. Certainly I would agree that filtering based on headlines/titles alone is silly. I'm not sure that's entirely what's happening, but that obviously plays a big role. One would actually hope that this sort of system would result in more content being read that otherwise wouldn't (provided it's of quality) in that - if people trust the system - they ought to investigate anything that shows up in it at least to the same degree, if not more so, than they would any other source of media. That being the case as long as one person actually takes the time to read something and discover its value, despite a poor headline, they can then call other people's attention to it, potentially giving it more exposure than it otherwise might get. Perhaps even more interestingly they can choose their own headlines to encourage more viewers, which throws an interesting twist into the whole thing.
Anyway I still come back to what the root of the issue is and I think one of the problems, if there are any, is these sites claiming (are they?) that they obsolete other media. They don't, they're just supplementary. I don't think *any* one form of media or media outlet very often truly obsoletes another, and this is no different. If they're claiming otherwise, well it's in their best interest to do so, it's simply marketing, and marketing hyperbole is nothing new. But it's definitely incorrect, and it can be annoying to hear that, and worse to hear people echoing it.
Yet this is no different from things that have been going on forever. This is directly reflective of how people always react to these kinds of systems, services, phenomena, technologies. It's just like fashion, which does intensely annoy me. Sometimes I even rant about it, so I suppose I can identify.
I guess I just wonder what all the debate is accomplishing; what end it is potentially working toward. Are you (or anyone interested in this) trying to show people that the marketing is hype, are you trying to get Digg to actually change for the better, etc? It all seems kind of undirected to me, like we could argue all day about it but even if we agreed... what then?