I learned the prohibition against passive voice in school, but I can't remember now whether it was in junior high or high school. Of course, that was back in the dark ages when we were taught to diagram sentences, too.
I had a devil of a time handling academic writing when I started doing that as part of my job. I was forbidden to use personal pronouns, but I felt constrained not to use passive voice, too, so you can imagine what a joke that was. I did quite well in college when I wrote history papers because they were in 3rd person anyway, but writing a grant proposal in the 3rd person was painful.
I spend part of one class session dealing with voice nowadays. Since almost none of my students are bound for academic writing, I explain that the general preference is for active voice, to show the actor doing the action. However, I also point out that choice of voice depends on the speaker's/writer's purpose. When I am describing the attack on me that took place the previous night, I will naturally use passive voice because I am the person of interest in the scenario rather than the unknown attacker:
I was mugged, not
Someone mugged me. Purpose determines the use of voice as well as so many other writing choices.
