It’s too bad that the article was retracted, because I suspect that the core thesis - that many wealthy parents push their children to extreme lengths to be successful in obscure sports like fencing in order to enhance their chances at admission to a competitive university - is essentially true.
It feels true. Or from my experience, participating in sports such as lacrosse, fencing, crew, water polo, ice hockey, wrestling, etc does tend to signal “rich white people school”.