Are they insane? "multiple antivirus", asking for trouble, I don't care what they say. If you must run AV, pick one and stick with it.
I don't think they're suggesting you run more than 1 AV app. I think they are saying it is good to have multiple apps available.
That said, none of that ***** will be installed on my Macs. You get a file from me and you have a Windows box, it's your responsibility to protect yourself from viruses.