Side note: Please stop using EU and Europe interchangeably, they are not the same thing. 100s of millions of people live on the continent of Europe, but not in the EU.
I don't disagree with you, but you couldn't really have picked a worst example (short of an an actual EU member country) given how their bilateral treaties with the EU means EU rules apply to do business in non-EU Switzerland.
Is not about the percentage, are you aware that you can't even mention you can buy a subscription from the website in the iOS application? Apple does not allow alternative app stores and is actively blocking you to inform of alternative methods of payment.