my opinion... without reading the article...
antivirus software on macs are really only good for finding PC viruses
i talked to the it staff at my school and they said i need it on my mac
i'm like "well there are no mac viruses really around"
and they said "it's for finding pc viruses more than mac viruses..."
so if you care so much about your pc friends... then yea use antivirus software
if you choose to live in a "dog eat dog" world, then don't waste your money and/or time