> I wonder why a US appeals court is needed for that decision.

Because it was an issue disputed in a US District Court case, and someone disagreed with the outcome.

> This should be obvious to any laymen who has heard that antitrust legislation exists.

The same decision (applying California unfair competition law on the headline question) also found Apple was not violating anti-trust law, so, your hypothetical layman would have come to the right conclusion only by coincidence, on the wrong basis.

My comment was sarcastic. Of course the legal system works like you describe.

The spirit of antitrust legislation is that competition should not be harmed by one or few dominant players. I would claim it is very clear that Apple (and Google) harm competition in the mobile space. If this cannot be prevented using the existing laws, new legislation is required. Monopolies and duopolies are harmful.

You might discover that even laymen disagree with each other far more often than you might think.

Most things that make it to court, and especially to appeals, actually have important arguments on both sides. If it's in court, it's pretty much by definition non-obvious.

So what is Apple's important argument? Hindering competition increases our earnings? We know best what the customer wants?

If you want to shitpost, i guess no one can stop you. But this is the end, not the beginning. It's a little late to demand someone bottlefeed you the merits of the case.