Additionally, if the app only has FB or Google login and you don't use either, you can just not use the app
Why should an app be listed as free if using it requires sacrificing my privacy to use it? That's fundamentally not free.
If the app cost me money then I've purchased an app I cannot use.
This is very simple: they're saying that you cannot require Apple's (and by extension your) users to submit to abuse of their privacy in order to use your app.
You're complaining that someone else is building apps in a way you don't like. That's their right; they aren't building them for you.
Why should Facebook?
Why should I have to get accounts for those services just to use your app?
Why should apple list apps that can't be used by users because of they require user's to create accounts with companies that are known to abuse user privacy?
The last point I think is the most reasonable: why should I, a user, be required to use some arbitrary third party just to use your app?
If you are solely using them for login support, and nothing else, then all you're doing is adding one more OAuth provider. What makes it so hard to require an Apple identity if you're already willing to accept google or facebook ones?
You are entitled to not use my app. I am entitled to not care.
The common and almost universally accepted understanding of "free" is "no exchange of money". Saying those who don't adopt an extreme viewpoint are lying is dishonest.
But what good would “open source tools” do overall if you still have to integrate with Apple’s services/APIs to do anything useful - the same is true with Android/Google Play Services.