Probably that. I'd assume they were pretty sure he was full on peaking but DFCs give enough leeway to DQ with prize. Or it is just way too awkward to pass down the prizes to everyone below top 8
I think it's because the ruling is "we're fairly sure" not "we're definite". If it were a court of law with "beyond a reasonable doubt" he'd go free. I agree it is a strange decision.