My theory is that snippet and reply may lead to taking quotes out of context and replying with an uncharitable interpretation of the snippet.
So while top posting may be less logical and efficient, I believe it may be more conducive to a friendly discussion.
Of course I could be completely mistaken about this, and it was just a coincidence that the communities I was involved in where top posting was heavily criticized had cranky people in them who would have found something to get upset about regardless of posting style.
Edit: I don't mean to imply that you are one of those cranky people just because you like bottom posting or snippet and reply! :-) Just observing something I noticed in online forums many years ago.
Whenever you start to see multiple quote snippets appear in an HN (or any forum) comment thread, it's basically guaranteed to have died and splintered into a bunch of uncharitable nit picks.
It encourages https://en.wikipedia.org/wiki/Gish_gallop.
>It encourages https://en.wikipedia.org/wiki/Gish_gallop
[Insert smarmy HN-stlye dismissal here]
I suspect that it's not just about taking time to inline quotes, but also simply about seeing what you're replying to directly next to your answer, as opposed to having it be separated by at least a large message header and likely by much more.
Another sad fact is that people re-invent inline quoting in Outlook culture all the time, badly: they manually copy relevant parts into their top-posted response, or they use some sort of color coding to write their own response inline.
> I like top posting.
I find top posting with inline, contextual comments when necessary, most useful.
> I find it makes things unnatural to read.
>> I like top posting.
My theory is that we're all so used to internet debates unfolding in snippet-and-reply-like formats that we associate snippet-and-reply with argumentative discussion by default.