Isn't it interesting how the choice of words makes such a difference and reveals the intentions of the author.
Heliblob uses the word "danger" because he thinks the risk is too large. If you replaced "the danger they are in "with the risks they are exposed to" it becomes much less dramatic and emotive.
Most activities and certainly those in aviation incur risks, but they are more or less balanced by some benefit. Becoming a pilot involves learning to manage those risks. One of the classic risks that comes up for discussion so often is the question of engine failure, especially in a single engine helicopter. In my view its role is over-emphasised - just take a look at the accident stats.
Most national aviation authorities are pre-occupied with engine failure. Perhaps in commercial air transport operations there is a case for this, because other risks should have been managed so that they are (or should be) well-controlled. However, in private operations pilots are permitted to operate in the avoid curve. Not quite all risk has been regulated away and there is a utility value to being there occasionally. If it is permissible to operate privately in that area, exposed to that risk, then surely it is appropriate for a student to be taught about these manoeuvres. After all, they are in the syllabus.
However, if it was me I would spend the least amount of time exposed that I could. This is both to manage the risks of the particular flight and also to teach the student about managing the risk. Example is such an important thing for a student. Don't sit in the high hover to debrief, but complete the manoeuvre down to a normal hover level, before debriefing. Professional helicopters minimise risk and only incur risk where it is necessary for the task. Some pilots positively like risk, but IMHO NOT professional ones. Perhaps that is one of things that distinguishes truly professional pilots (rather than just those with a commercial licence).
Heliblob does not tell us enough to know whether what the instructor was doing was reasonable. His suggestion about a third party getting involved sounds premature to me, putting it politely.