Thank you for explaining that! Seems a tough call doing that versus flagging the root comment of the acrimony, but maybe that alternate approach would have a bigger (too big) cost in disruption once there is such a small continent of comments built out under the top comment.
We can do that too, or at least mark the low-quality subthreads offtopic (which downranks them). But if we don't take the provocation out of the title, it'll only generate more of the same.
There's also your brilliant practice of collecting off-topic threads under a "sweep" comment, which strikes me as astoundingly effective at re-railing derailed discussions.