Well then the thousands upon thousands of homes with brick fronts here in northern Va (greater D.C. metropolitan area) are all wrong then.

Who, with common sense would think that a masonry box (metal) could possibly be any better than a plastic nail on box? The plastic box will outlast the masonry (which in my opinion is a bogus term anyway) box as it will not rust and also the plastic boxes holes for the screws are deeper and grip the threads for a good half an inch as opposed to a masonry box for just the thickness of the box which alot of times has to be retapped as over time it loses it's gripping power. You can only retap those so many times before it's bye bye. Show me a code reference (which I've never heard of) and I'll still continue to use plastic since every inspector allows it.