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If they're effective at creating extra charitable donations from money that people would otherwise spend on sweets, then fine they're worth it even if the take a large fraction of that extra money home.
On the other hand, if they're effective at making their charity more competitive so that it captures a larger slice of a fixed size donation pool, then taking a large fraction of that extra money home is taking away from the total amount that will actually bet spent on charitable things.
But how much of that $24,000,000 would have been dontated to other charities had ALS not been chasing it so effectively ? I actually have no idea, but I expect the answer isn't none.