Re: Zazen necessary for training
My understanding is that zazen is actually a specific meditation technique connected to zen dogma. In addition to sitting in one of a very few specific postures, one is also instructed to focus on the sensation of breathing and keep a repetitive count of breaths, usually up to 10. If the mind wanders, one is supposed to return to counting at 1. Over time, the mind wanders less and the attention does not waver from counting and breathing, thus quieting what they call the "monkey mind". I know of several other types of meditation, which can be done while seated, which are not called zazen.
However, it could be that the term was being used more loosely than what I have encountered. My thought would be that in this case, they are misusing the term, but maybe an actual eastern religion/philosophy scholar will show up to clarify.