Your attempt to somehow conflate it with someone's business models are laughable at best. All software comes with strings attached. And the biggest one is: even people who distribute software for free still have a business to run and mouths to feed.
Or indeed that post's parent, where a different opinion was offered about when a license for CoreML libraries was paid. https://news.ycombinator.com/item?id=32905596
Or its parent, the one which initially defined the scope of the discussion, which was "...Apple charging a license for the frameworks and tooling they provide..." https://news.ycombinator.com/item?id=32905555
Not about the Xcode IDE itself which I agree is free-as-in-beer. (Though others might disagree — an argument could be made that it was paid for the purchase of a relevant Apple hardware product; the fact that it wasn't pre-installed being a mere technicality.)
If you want to lump that in with free as in beer because Epic isn't taking money from people who haven't made something particularly profitable, okay, but I don’t think many people would agree with you.
(It's also free-as-in-you're-part-of-their-marketing-strategy. Widespread "free" use of Unreal Engine helps build developer experience with Unreal Engine, increasing the availability of relevant skills in the job market, and making its use more attractive when it comes time to start a big, highly profitable project.)