Trojan viruses

From the news  was I read  the advanced technology could not escape from a Mac computer crime virus.Although it is can says that one of the technologies that  in trust it can not be reliably prevented from harm virus.Komputer Mac operating system from Apple attacked by a malicious program from the variation there are trojan named Flashback.From the begining reported that 550 000 infected Mac computers for botnets Mac.Then growth after the analysis that the number of infected computers increased to 600 000 Mac.More dangerous  he could masquerade as the installation file Adobe Flash Player.And then, who is responsible for all of this? what about the consumer.,,,