So since we only see the charge sheet and don't have any of the context it's really hard to say what is an is not legitimate.
I will say this. The training conducted during FOW is supposed to specifically planned, executed, and approved. Also PT during FOW is only authorized at specific times in the training schedule, in specific context, and by specified cadets. Additionally corrective PT is generally not authorized until a certain point after FOW, and again must be done in a specific fashion to demonstrate its connection to actual training.
So if these cadets violated the approved training plan, and conducted these activities in a manner that was not authorized during FOW then they would be in the wrong. Now there may be an argument, between is this being hazing and some other type of disciplinary matter, but either way not following the approved training plan isn't a good thing. It's easy to forget sometimes that in the University's eye the Corps is a student organization and must go through the Student Conduct process just like any other organization. However unlike other student organizations any student conduct case dealing with the Corps must have a member of the Commandant's Staff as part of the investigating team, and the proceedings. There is no kangaroo court, there is a deliberate investigation, and a hearing, before any determination is made.
I'm always a bit confused by the outrage about the Corps being different from what it was years ago. It's been over 15 years since I was a cadet, and I can say I never got anything good out of being crapped out in my COs room after pulling his boots. Or being crapped out with 46 other fish in the showers, in winter PTs, rain jacket, and watch cap. I mean it makes for some funny stories but that's really about it. I wish I would have done less of that and had better grades, or made more friends off the quad, and so on.
People keep saying that new Army is soft, and these types of things have ruined the Corps. However I keep meeting recent graduates who are Army platoon leaders, or new SF ODA commanders, and they seem like sharp, tough, smart people to me. So I guess I'm ok with the direction things are headed in.