You don't understand, do you?
The average apple customer values the consistency of experience in the platform far more than your application.
In the grand scheme of things, I am pretty sure you removing your application from the apple store would be an objective loss for customers, but that loss pales in the sight of the benefit of not being compelled to use google or facebook as the only way to login into an application as it is so common in android.
The average apple customer values consistency and is far less tolerant of deviations from that than the average microsoft or google customer. The whole point in paying more for apple is because we value order, predictability and consistency.
Windows customers are not used to that. Windows Hello may be a good thing for them, but they don't expect the same degree of consistency, if your windows Application doesn't use it, they don't complain, this is life.
But apple customers, like you it or not, expect IOS features to be widely available on IOS applications. We literally pay for that, and as there are vastly more consumers like me, than developers like, it doesn't matter if we bought half the hardware you buy, because as a customer class, end users absolutely dwarf developers.
I completely understand your personal frustration. But this is on you, your choices of providing your work for free deliberately.
Most customers don't want to be back on the situation where you either choose between facebook login or tedious manual account creation, just because it will inconvenience some developers. The whole, raw point is exactly that. It may sound cruel, but we WANT you to be forced to implement stuff that is consistent with IOS guidelines, best practices or even features. Customers can be cruel like that.