I have only anecdotal evidence so this is a fair point. However I'll point out that I have not seen the experts provide facts or research either so it appears that they have the same obligation.

In fact a cursory survey of the research I can publicly get access to indicates that parent-child, or teacher-child interactions are considered very essential for moral and social development and there is very little mention that I can find of inter-child interactions as a critical part. Most of the research that I can find highlights the importance of adult-child interactions. If you can point me to some studies that counteract that I'm interested.