The reason people care about what he is being given on the flight is because these are generally seen as perks that a felon shouldn't be given. This involves the presumption that if good upstanding citizens do not have the opportunity to drink champers, then why should criminals!?
This in turn might stem from the use of the legal system as that of a vengeance distributor rather than a justice system. It's almost impossible for a plaintiff to say "I just want justice" and be completely honest, no matter what their aim or emphasis might really be. We see crimes like rape and murder as things that disgusting, sick people do, or perhaps the people who do them should be deprived of their rights, so that the justice system's punitive measures are really supposed to be a denial of various freedoms.
A more relevant application of this concern (the product of an extension of public hype) would be in terms of what effects granting perks to convicted felons/assumed criminals acheives. There is debate and outcry in Australia over the various perks granted to various criminals such as cable TV and a sandwich toaster- as a reward for "good behavior". This I suppose is justifiable only if the general behavioral problems in prisons were considered, but in terms of rehabilitation so that convicted felons will no longer run afoul of the law, the effectiveness of what are essentially temporary bribes must be questioned.
That said, a confession is not a guarantee of guilt, as the defendant's lawyers claim. Your apparent objection to his not being slapped in handcuffs is in fact almost exactly the same kind of thing as the objection to what he ate on the plane. He doesn't need handcuffs as he is not to be treated as a criminal until proven beyond reasonable doubt that he is in fact guilty of the crime he has been accused of.
All this said, I think most important is the criticism of the police handling of the whole deal which allowed the media scrutiny in the first place. This should not have been brought to public attention at all.
