I've definitely heard to avoid *over*-using passive voice. I think it's taught that way in school, just as not starting a sentence with "and" is, because otherwise kids will overuse it:
"They got off the bus. And they went into the house. And they got a snack."
etc. But generally a more-advanced writer is able to get away with starting a sentence with "and" because they know where and when it's acceptable, and they don't do it constantly. Same thing with passive voice, I think.
"They were dropped off at the house by the bus. A snack had been prepared for them by their mother. The youngest one was bitten by the family dog."
Ick. But when interspersed with active voice and used mainly when appropriate or for affect (I find it useful to avoid personal pronouns without making it very obvious to the reader that I'm doing so), I think it's okay.
