Lumifer generally does not address the entirety of the comment, instead selectively quoting several sentences from various points in the comment and then snarking at those.

There is a reason for that. Addressing the entirety of the comment usually requires that your answer be longer than the comment you're replying to. That leads to large walls'o'text of fisking very very quickly and the whole thing implodes shortly afterwards.

In my experience to keep a manageable conversation going for more than a couple of rounds you need to severely prune the topics and keep the whole thing on a (possibly meandering) track. Of course both sides can/should do this: I don't expect that every point I raised will be addressed in the reply. As to snarking, well... :-)

Re EDIT:

Snarky one-liner? Check.

I like snarky one-liners.

Does not actually address the main point? Check.

Nope. It actually addresses the main point of the post it's replying to.

More condescending than informative? Check.

Not condescending. Snarky (see above). Condescending would have been "Don't worry your pretty little head about it".