I was under the naive impression that these newsgroup forums were monitored
by
a group moderator whose duties included removing viruses, spam, etc.

Not all newsgroups are monitored. This one is not. Sometimes the spam even gets
into the monitored ones.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)