I Might Be an Overly Concerned Parent

So I recently enrolled my kids in a karate class. It's supposed to be good for them, exercise, discipline, self-confidence. But I found out something rather concerning last week. While waiting outside the studio during their practice sessions, I overheard some parents talking about their children taking shortcuts in schoolwork and social issues by relying too much on the instructors or using the karate classes as an excuse to skip other responsibilities. I tried to rationalize it at first, maybe they're just sharing information casually. But then one of them was very specific about how their kid was struggling with homework because of practice times. Another mentioned their child skipping meals, which I couldn't ignore since my own kids have been asking for snacks between dinner and bedtime lately. I approached these parents to discuss the matter more deeply but felt like an overbearing busybody as soon as words started leaving my mouth. They seemed a bit taken aback and maybe even defensive. It made me question whether I was being too intrusive or if I should have just kept quiet and dealt with it on my own. I'm torn because, on one hand, kids need to be accountable for their actions; they shouldn't use something as enriching as a karate class as an excuse to slack off elsewhere. On the other hand, is this really any of my business? It's hard when you feel like everyone else around you might have better answers but can't find them. So here I am, unsure if I did the right thing by talking about it or whether I should just stay silent and hope for the best. Am I being too nosy, or is there a way to be proactive without overstepping?