These discussion are hard. No one likes to think about these things, after they happen.
The truth is NO ONE IS TO BLAME. Things happen, we have all been in situations we should not have, and shit happens.
It seemed the wrong questions were being asked, trying to assign blame to the "GUIDE" or "company", as if they hold fault. Avalanche's happen. There is not "right or wrong", there is only "choose one thing over another", because of information, or even in the extreme example of the person who never checks snow history conditions, slope angle, or ignores obvious visible signs. All pure chance with different approaches and reactions/actions.
I think it's the inner safety jerk coming out in me asking all the questions. At work I'm a safety guy, and we're always speculating about why things happen. The current theory is that everything is preventable and there is no such thing as an "accident" although the real world certainly doesn't seem to agree with that theory.
In the early 90's we had the stupid worker theory, where they basically blamed all accidents on a workers poor behavior. After that there was a period where it was all managements "fault" (although we don't actually find fault or blame in safety, we look for immediate causes and basic causes).
So looking at this incident here: the immediate cause that somebody was buried in an avalanche was that they were snowboarding where an avalanche happened. The basic or root cause of that is where it gets complex. Again there are multiple causation theories which basically say that no one specific event or person caused the accident or allowed it to happen, but several things contributed.
1) In this case I would say (potentially) proceeding into the backcountry under an avalanche warning could have been a basic cause (again, I'm not 100% sure if the area they were in was under a warning)
2) The guide may have made a mistake when assessing the conditions, may have not assessed the right area, number of areas, etc.
3) The group may have strayed away from the guide, or taken a wrong turn
I guess what I have trouble accepting is that this kind of this "just happens". Bastard children just happen, getting killed in an avalanche doesn't just happen. I don't want to promote assigning blame, but I think it's healthy to debate the possible basic causes of an incident to see if there's a way of preventing it from happening in the future.