You must have left out some links somewhere.

I couldn't find anything that said "Expressing an opinion about whether
a post might be appropriate for a particular newsgroup" (i.e. a cut 'n
pasted political editorial posted to a
recreational boating forum) "is the ultimate example of disgraceful
conduct on usenet."

There are reasons that (most of us) will cover our mouths when we
sneeze, say "excuse me" when we are forced to step in front of
somebody, use expressions like "please, thank you, you're welcome" etc.
Simple basic manners. Manners indicate that a person is aware of the
impact his or her actions can have on the society around them. Then
there are those few who feel that when they sneeze the object will be
to see how far the spittle and snot can fly, that anybody dumb enough
to stand in their way should be rudely shoved aside, and that other
basic courtesies are needless. A lot of people ultimately act
ridiculously simply because they can.