You definitely need to read William Dalrymple book on the Koh-I-Noor to be more informed.
But the fact of his age at the time he signed the treaty, it’s very emotive and I don’t think particularly relevant to the outcome.
Really? Have you not heard of something called the Rule of Law? Or the importance of just wars rather than blatant invasions and land grabs?
The emotive instinct is that something isn’t right (like, duh?!). Gut instincts here are trustworthy in saying that something is wrong when a ten year old signs a treaty like that. It needs to be probed further.
Dalip/Duleep Singh’s age challenges the legality of the treaty. Legally, he is classed as a minor. If his mum was on the treaty then at least you can argue there was parental consent. But she’s not.
Dalip/Duleep was clearly important enough to be on the treaty. So it’s reasonable that he ought to understand what he was signing away (essentially the loss of his inheritance). You kinda need to jump through wildfire burning hoops to prove a ten year old in his situation would have the capacity to understand the magnitude of signing that treaty, especially without independent counsel and/or a legal guardian with his best interests at heart.
Duleep/Dalip would argue in later life that the treaty was unlawful in both British Law and Christianity (which was important to Queen Victoria). He had a point. So it was discussed in parliament at the time - and it made some very powerful people feel too uncomfortable to acknowledge any wrongdoing so they went on the defensive (people don’t like being told they’re bad people, especially proud people). Anita Anand writes about it in her book about his daughter.
It is also emotive because it’s about taking advantage of child and that amounts to abuse. Or do you think that’s ok?
The story of Dulip Singh is a personal tragedy
He was also a royal in his own right and represented his people and homeland. William Dalrymple notes that his tragic story is still, to this day, keenly felt by the people in the Punjab, so it’s a matter of state and diplomacy too.
It’s an awful thing to do to a child, but he was used to humiliate the people into submission.
In modern day terms Duleep/Dalip Singh would likely be entitled to significant compensation, if not the crown itself.
Imagine if something like that happened to a young British royal? The people would understandably (and rightly) take it personally because of what royalty represents to the nation. So, no, it’s not just a ‘personal tragedy’ it’s more than that… he was their last maharajah. This is about the crown.