I dunno, certainly some tags are justified, such as distinguishing submissions which are publicly-readable versus ones which require an account--or worse, payment.

That's not a value-judgement of the true content of an article or piece of media, but a fairly objective facet which impacts the HN participant's experience.

It's kind of like how, back in the day, people really wanted to know the filesize of something before they clicked, to avoid a blind-investment of their dial-up bandwidth for indeterminate minutes of waiting (and opportunity-cost of other things not downloaded) that might be more than they really wanted for whatever-it-was.