As far as the kids, I don't think too many lubavitchers still have trauma from missing the meal
Things don't have to be traumatic to be less than optimal. And besides, there are plenty of things previous generations felt "weren't traumatizing" the kids which were. For instance, lack of validation. Think about this as a response instead:
"here's a link to the reasoning behind our minhag. As for the kids, yeah, I totally see how that sucks to have kids miss out on such a massive highlight of the week, and how late meals can ruin an older child's schedule and cause them to be overtired and cranky on Shabbos day."