I think that it's extremely important to understand that our makeup is primarily based on the years up until our early twenties, as they are when our chakras more fully form. For example, if something is suppressed based on a parent yelling at us, then that can heavily influence us from having energetic blocks form; health issues and mental problems are more likely to manifest as an adult. One of the best resources to understand some of the concepts around this which I have come across is
Working With Your Chakras by Ruth White. My detailed article on the chakras
here on the forum can also help a lot, as all this heavily relates to how you bring up your child.
I wonder how those children will cope with business/real life situations in the future. They better be prepared to handle rejection, conflict, jealousy, stress, etc., and yes, even somebody raising his/her voice at you, which is normal for example in the work place.
In terms of the above article and situation the parents have created with their children, if they have strong social circles with other children their age who they can bond with and who resonate more with who they are, then I'm sure that that is a much healthier environment that any public school system on offer in the western world. If they are traveling the world for most of their childhood, that would present them with many social situations so I don't see an issue with that, as they would likely have a larger variety of children/friends in their lives than remaining at the same school.
With raising our voice, if we are not coming from ego (anger, rage, frustration, fear, etc) and we have the right body language (which would be natural if we were not coming from ego), then I don't see an issue with speaking a bit louder to make someone pay attention, but most of the time this is not the case. Sound is everything, so if we present our words in the right way, we can speak loudly and it then will not cause harm. For me I am very sensitive to people shouting, not just from being an intuitive as I pick up on the energies and vibration behind words (as well as being empathic to peoples emotions), but also because of how I was treated when growing up in terms of my shadow and inner child. I had to go through a lot of healing from dealing with my parents having raised voices, and I see this as a very negative and unhealthy situation, which of course made me who I am but continues to partly influence how I react and respond.