If you don't have children of your own and are able to save money for your niece or nephew's education or future needs, that money should be treated as a gift, not a right. Kids and teenagers are naturally curious, consequence-averse hurricanes of impressive destruction, and punishing someone's future for one morally divisive mistake can be a difficult choice. However, the decision about whether or not to give a significant amount of money to someone is ultimately up to the person giving the money, and if petty thievery is a major deal breaker, that needs to be respected. Pro-tip: don't steal from people, but if you're going to, maybe don't choose your aunt or uncle with your college fund, dummy.
So, when a financially savvy person decided to consult the moral compass of the internet otherwise known as Reddit's "Am I the As*hole" about whether or not they were wrong to deny their nephew of their college savings based on his questionable behavior, people were quick to help deem a verdict.