I think when you choose to sell your products on Amazon, or host your videos on YouTube or use FB login for your app, you're necessarily taking a risk by depending on a third-party for your success. It's possible to create your own login system or host your own videos or own your own e-commerce site and there are even a whole host of valid competitors for all these services too.

Would it be better if, instead of analytics, they flipped a coin?

Yes, because if they had to flip a coin they would buy fewer companies, which would lead to less market consolidation.

I know you're being facetious, but it might actually be?

In nature, random mutation leads to greater genetic diversity and speciation. In some mathematical optimizations, introducing random noise can help avoid getting stuck in local maxima.

Using analytics to restrict apps based on their popularity - if that's what Facebook did - is definitely much more anti-competitive behaviour and even more likely to hurt growth than simply being arbitrary or completely random in their decision making. But yes, a non-arbitrary policy of allowing developers access if they followed a transparent set of rules would obviously be better.