The market in question is licensable smartphone operating systems, which is not a market Apple operates in (edit: well, other markets are involved too, see sibling thread).

They (Commission and Court) never claimed that there aren't any markets they both operate in (which there obviously are).

See the decision for more details, AFAICS it talks about Google's claim that Apple provides enough competitive constraint starting from section 145: https://curia.europa.eu/juris/document/document.jsf?text=&do...