I now think the best way, based on recent experience in controversy here, is to reply once, then disengage (defnitely by post, possibly by vote). Replies past the first post and response generally end up in horrible, dark, and uninformative places. I've put myself on a one-reply diet now.

There is not enough time in the day, and not always enough meat in the post, to go replying even once

Sometimes all one can do is downvote and move on

Looks very trollish to reflexively reply this reply is offtopic, factually erroneous ... and this guy won't stop posting them