Hans Zimmer is hardly the most creative or original of composers and as you say, he has to buy in the knowledge that he lacks.
I don't agree that he isn't very creative or original. Regardless, he writes great music and that's all that should matter. Not every wondrous, complex, and beautiful piece of music involves having previous knowledge of vast or minor theory nor does it require "buying into."
The truth, with very few exceptions over the last 600 years, is that the most creative composers study the theory (almost always with help) and then apply and/or develop it to suit their artistic vision.
Really? So, the only the most creative people have studied theory or have had help? According to whom are these people the "most" creative? You can't possibly be saying that lacking knowledge in music theory will always make you "less" creative than the "most" creative that have studied theory? I can't believe I'm even entertaining such an absurd argument. Unless, I'm totally misinterpreting what you're saying.
What exactly do you think he's joking about? Because a great amount of the most technical and heaviest metal bands around the globe, in fact, do share far more in common with classical music than you'd think.
Music theory is simply knowledge and how does having more knowledge make you worse at doing something? Honestly, do yourself a favour and learn some music theory, while you're at it, some recording and mixing theory wouldn't hurt either.
It wouldn't make you worse at writing music, but that's not the point here. Maybe he doesn't want to learn theory? What's wrong with that? Maybe it doesn't interest him whatsoever? So what? That's his prerogative. Now, I wouldn't say theory is the devil or anything. Or that it's useless. I don't have a problem with anyone knowing or learning theory. Theory is enthralling, fascinating stuff, no doubt about it.
What I have a problem with is the elitist condescension going around when it comes to writing music or pursuing your passions -- whatever that may be. I won't assume this is the case for you, AudioExpert, but in my experience, I've met a LOT of far more technically superior artists than myself, but they can't write a good piece of music to save their lives. There's no heart in it. It's all a numbers game to them to satisfy an equation, but not to satisfy an emotion. Not to mention, they're the most arrogant and inflexible "artists" I've ever come across. I'm just relaying facts of my experience. Knowing theory does not necessitate a metamorphosis into being a complete jerk. Not everyone is like that.
If you WANT to pursue learning theory, the best way to do it is to make sure FIRST that you love writing music and that you can put together a good song. THEN once you've matured as an artist and you understand the basics of sounds, chords, melodies, arpeggios etc., go ahead and get some theory under your belt...IF YOU WANT TO! But, please, spare me the "you're not good enough without it" BS. This goes for the other way around, too. There's nothing wrong with knowing theory either. It is very fascinating stuff and can add another layer of fun to your work.