I have zero knowledge about this situation, but I'm been around long enough to witness an interesting interaction between problems and rules in life.
When there's a problem, the natural reaction is to create a rule/law to deal with it. But in trying to precisely deal with the problem, it's easy to create a rule that's overly complex and too hard to implement/enforce.
Clearly, some stakes have amassed quite an amount of funds. Given that youth camps happen every two years, it makes sense that the units will need to carry over "off year" funds to finance the camp years. But to do that exactly gets into the details of how each unit is handling their camp budget, as well as other area approved but less common activities. It's understandable that the church is going to want to find some simple approach that still tackles the bulk of the problem instead of trying to stamp out every single abuse.
The fact that the church has decided on a simplified approach of taking anything over 50% of the stake total allotment from just the stake suggests to me the magnitude of the problem they were seeing.