Free buzzing is a good way to get somebody quickly on the instrument, but I fear that it does more damage in the long run. Why? Beginners tend to make "farting" sounds, if you will, without any airstream backing them. Perhaps, this is part of the reason that beginning band concerts sound more like quacking ducks than anything else. "Buzzing" is not really how brass instruments work. The resonance of the instrument, along with a constant airstream passing through a properly formed embouchure creates a standing wave throughout the instrument. It doesn't even take all that much air (in terms of volume) to begin with.
I like to think of a "rushing river" of air passing through my lips and the instrument. The vibration should be almost automatic if things are correctly formed.
We need not be too critical of the article, however. We sometimes split hair over things that seem obvious to us, but not to the rest of the world. For example, I work as a software developer. Therefore, everybody assumes I know everything about computers and can fix their busted printer. Not so! I just write software. However, it's OK if somebody says I work in IT, even though I technically do not, because it may not seem so obvious to the outsider that IT and Software Engineering are two different curricula.
