that is correct, no system is 100% perfect or safe from viruses. and the problem is, Mac users tend to be very bo-chup (a common reason given for switching: "oh i dono how the dam windows PC works so i use a Mac and it works"
this form of ignorant and apathetic thinking is very dangerous ("i don't know how to use an antivirus program, so i didn't install one. besides, Macs won't get hit by viruses anyway")
a lot of people are lured by Apple's designs (me included), but like all shiny new machines, attention must be paid to what works under the hood. but i agree Macs do reduce a lot of headaches for the less computer-literate.