Your point of view doesn't baffle me, because you said this:
"Why shouldn't we be willing to debate and explore a subject in depth?"
Good question! I would be happy to debate and explore political ideas in depth. (That's why I hang around some politically- and economically-focused blogs, and I chat about politics with my friends, and I read the writing of experts.)
But how on earth can you call Hacker News posts about politics "debating" or "exploring a subject in depth?" They are the absolute opposite of depth! Pseudonymous, evanescent discussions, where you stick around for a few hours and a few comments at most; you have no commitment to defend your words or argue sincerely, and half of the commenters don't know what the other half said last week on the same topic. Could you possibly think of a worse format for "debating?"
At the very best I have ever seen, Hacker News debates are someone who sounds smart stating a reasonable-sounding position, and then someone else who sounds smart suggesting that there might be reasonable-sounding problems with the reasonable-sounding position. Then after a dozen posts about the position it's off the front page and forgotten. That is the nature of this medium. Usually, everyone just lines up behind their premeditated arguments and fires upvotes and downvotes at each other until they see another interesting post.
Places that are reasonable for debating and exploring a subject in depth: A small, focused community that's willing to build on their prior discussions over the course of months or years. Talking with friends with whom you have a shared, growing, and conscious context in common. Books, essays, and other long-form prose where you can present your whole position at once. NOT here. At least I've never seen it happen, and I don't see how it could.