i think that's a good point that that guy is a professional. you wouldn't bust a guy's chops who's about to make you two hundred million bucks over technicalities, would you? prove to these guys you can make 'em lots of money and you might be able to send your script through smoke signals. until then....
like JR said, avoiding passive words is just better writing. that's really not debatable, being one of the few hard writing rules everyone should adopt. there are certain words that lead to passive voice, like 'was.' i believe this because i'm saying it, if you remove one word with passionate aggression, make that one word 'was.' sure, professionals use it, but it's not because they can't get rid of it. there are only a few times when i can't get around it. i think some professionals are just lazy sometimes, like the guy who wrote batman begins. he *knows* how to write, he just doesn't have to go to the same lengths because he's 'arrived.' as a newbie, i bet he'd have a lot harder of a time passing that off, no? i see this as one of those examples of focusing on different writing skillz as a novelist than a screenwriter in terms of what you're trying to be the best at, if that makes any sense.
seriously, as an excercise, go through an old story and eliminate every single 'was'. don't half-asss it, kill 'em without mercy. reread the story. i guarantee it'll be better or your money back.