You are missing the point. Being triggered by sound or light means the malware can be activate by a global hack on the world's TV stations, just like happens on bad sci-fi series.
Android devices world wide will rise up and take over when the call to arms comes over the airwaves. I'm imagining a nightmarishly robotic and shadowy figure flickering across billions of TV screens, screaming "ACTIVATE! ACTIVATE!"
At that point the malware Android army will simultaneously post inane and vague status updates onto everyone's Facebook, then self destruct. No-one will be able to reply except for users of Apple and Windows, and all Android users will wither and die alone in a desert of dis-communication.
That's the nightmare scenario the writers of this dumb study had in mind, isn't it?