It's a good point, in that I imagine the submitter is hosting an ephemeral salon of sorts: much of the atmosphere easily prepared, and no need for chairs, greetings, or snacks.
So I do feel one ought to play the host for a bit, reply often, and expect replies during a certain window.
On the other hand, I lack a lot of expertise in the submitted link more often than not, and the sole motivation to submit is "I think HN would find this interesting." Still, it would help to set context in a way, and filling in the first comment would do that (even to initialize the "host's level of knowledge"). The comment could end with a topical question.
For me, /newest is like the borderlands, and the core hub is the front page. Sometimes I can visit the bustling downtown and drop in on some really deep, insightful discussions. It's cool to see a new link also appear on the front page that I had upvoted--almost like "validation of the tribe."
After reading the comment from skilled, I don't feel as bad about submitting without a comment, but in the future, I should take your thoughts to heart and at least say something, even just to answer why I thought it was interesting. (Just me, though.)
Of course, that first comment should come with the implicit preface that it might have been a totally random collection of neurons that coalesced to a spark of mind to submit the article, hopefully to be overtaken with others weighing in.
The comment from krapp is also a good point, so that's another consideration.