def: willfully causing pain or suffering to others, feeling no concern about it.
Shaming is undesirable, but I wouldn't say publicly knowing how you rank compared to others would constitute "cruel". Its really how the world works - in sports you see exact stats of how your do, publicly traded companies/CEOs are meticulously analysed publicly on how they perform etc. etc.
There does need to be a balance btwn hypercompetiton, and "everyone gets a trophy" mentality. I feel like the US has swung far to one side and china the other. Best would be some where in the middle. Maybe have a live list of the top 10-15% of student scores.
I am a parent, and don't want to hurt my daughter, but at the same time a little pain and suffering makes you stronger.