The judges were careful to stress that the ruling didn’t represent any comment on the sympathy or otherwise it was reasonable to have for Begum – rather, that there was nothing unlawful in Sajid Javid’s deprivation decision.
Um, that's how an appeal works? It doesn't re-litigate the entire trial; instead, it focuses on whether there were any problems with the system: did the lawyer sleep through the trial? was the law mis-applied? was the defendant coerced into a confession? etc.