For people with three thumbs and a trunk to keep the axiom in:
People who point fingers and call names should not complain about finger-pointing and name-calling; unless they are being ironic for rhetorical effect, which may or may not work.
People who comment on blogs should not criticize other people for blogging; although it always strikes me as humorous, and I appreciate the smile it gives me (even if it may look like a smirk).
People who excel at snarkiness should not take offense when others are snarky. (I should say, however, that I really like this word, "snarky," which I heard for the first time earlier this year, and which I have since been enjoying in a wide variety of contexts.)
Better to shine a light than cursing the darkness. Kudos to Dr. Kleinig for that most excellent wisdom. Now if I could only master doing it.