Fair. I accept your analogy it's very reasonable. But the few questions you have to ask isoh god, why am I going down the rabbit hole lol...
your neighbor giving you cookies for free daily is a gift that gets nothing in return for them. you are also unlikely to need the cookies to survive (its a cookie after all) so if you stop getting them it doesn't have a material impact on you aside from wondering if you neighbor suddenly hates you now or something...
the better analogy is this...
you own a giant theme park like Disney World and have built a highway to it. in addition you offer up your free and un-used park land to anyone willing to build additional highways to the park to bring more customers, but they have to bear the expense of building these additional roads. in exchange they can charge tolls on their roads but because these road developers know their roads are better and more convenient for many of the parks visitors those same visitors will happily pay the tolls to avoid the crowded and less desirable main road. then one day Disney World says "in 30 days we are closing and destroying all the extra roads and everyone has to go back to using the one single one we built. if its less convenient to our customers who have spent the last 10 years driving other roads, we don't care. if you built those additional roads, sorry but you have to destroy your investment in their construction and make a new plan for your lives." legal... but very anti-consumer and a terrible way to treat your partners who HELPED your business become what it is.
1) Were the highway developers fairly compensated in this whole deal despite the rapid shutdown? For example I agree with you if Apollo spent 2 years of his time building this and then the API got shut down after 1 year. He would've lost money or worked at minimum wage. That's unethical. But this isn't the case. I repeat, the dude earned a whopping 2-3 MILLION dollars USD. I think it was a fair exchange by all accounts
2) The second thing you have to ask is, were there any level of deception? At court, they would ask even if there were no signed contract, were you ever lead to believe that the service would be provided for X amount of time as 0 cost? In this case, none. It was Apollo's assumption that it would be free (or cheap) forever, and willingly taken the risk to invest in building this product. And indeed, he profited but just not indefinitely that he wanted.
3) And finally in your analogy, the exchange is calculated and willing from all sides. Disney wanted investment from others, developers wanted to profit (for an unknown period of time). At any point in time, if either party left it's fair game. Flip the story around. If apollo just one day destroyed his app (with 0 notice), and took all its users away from reddit. Users are left with a choice to return to default app or stop using reddit. Is this unethical? I'd imagine your answer must be no. Why? The only difference again is that this generation of people have an extreme anti bias towards corporation.