They're made for morons that don't even know how to turn on a computer.. how can you call yourself a "webmaster" if you can't even prevent yourself from getting a virus?
And the antivirus programs don't always stop you from getting one they might just tell you you just got one, which is pretty pointless. Anyone who works via a computer and the internet should know when something is suspicious and be able to tell when they've just gotten infected.
