OS X was very safe (I won’t dare to make any claims about security) for a long time exactly because PC viruses couldn’t touch it. That’s a real and practical benefit. OS X users didn’t have to deal with viruses. To an extent that is still true – but it has now also become true to an extent for Windows users: They also don’t have to deal with viruses any longer, even if they take no precautions at all (at least most of the time). So that advantage has disappeared and if Apple continues to move so slowly the balance might tip.

Still, I can’t find anything wrong with the marketing language they used.