The court cannot make Apple be sincere in an apology if Apple believes they are in the right. Just the same way Sally's Mother cannot make little Jimmy sincerely apologize for tattling on her daughter when she copied his homework, especially after the teacher already praised him for bringing it to her attention.
Your analogy is deeply flawed. Apple had a choice as to whether to bring this matter before the courts and UK judge has no vested interest in protecting Samsung. There is no 'teacher' figure in this case; no more objective person involved in the case than the UK judge.
If Apple had no respect for the court's opinion, they should not have brought the lawsuit. In bringing the suit against Samsung into that court, they have effectively asked the court to pass judgement and agreed to respect and abide by the decision. The entire problem is that whoever is in charge at Apple believes they are in the right and that the court is wrong; the statement shows a lack of respect for the court and therefore is, in a way, a challenge to the court's authority. This is the judge's way of reminding them that they should respect the verdict and comply with it.
The only resolutions to this are Apple complies fully, or stops operating in the UK. The UK court system woud much rather get rid of Apple from the UK than allow a challenge to their authority to stand, and Apple would rather continue to operate in the UK than flounce out over a matter like this and lose the UK (and potentially the EU) market. Apple should have folded before, and should definitely fold now. The longer this silly game goes on, the more they have to lose.
That is to say, it'll be a hard time getting Apple to believe they were in the wrong because a different court has already said their accusations are correct.
It's hard (unreasonable?) for someone to admit guilt when many others are shouting that they are in the right.
Since Apple is quite happy to see judges' will be done when Apple wins, their statement in defeat was not at all classy.
EDIT: The court case counted as negative publicity for Samsung and I don't think the court thought that a fine would counteract that publicity.