Earlier quoted context omitted.
Their core business is that monetization, by definition. The NFL is primarily sponsored through network agreements, which themselves are primarily sponsored through advertisers. Is the "core business" of the NFL, then, advertising? Of course it isn't. Such an argument is specious to the point of uselessness, and only appears in the form of rhetoric. The NFL's core business is making an entertaining sports product tha…
Google sells ads on third-party website properties. The parent's argument is certainly not specious.
Apple operates and promotes its own ad network, and its lack of success in that market doesn't somehow separate it from that reality. No one would claim that Apple's core business was iAds.