I don't think you're necessarily wrong, just that we might be missing finer details. This is similar to what I've been thinking, too. For a little while I thought it was a ghost or something but before that, I thought it was nanites. And then after I gave up the ghost I went back to thinking it was a virus that's able to detect and pinpoint certain factors in us to choose a new host. It has to have some level of intelligence to know when to be active, when to be dormant, and when to control our friends to say and do certain things.

That doesn't mean its perfect. If someone tries to fight back, it could become unstable. [ ... ] I guess what I'm saying is...I don't disagree in the possibility. At all.