Apple (and every other company) is already subject to tons of consumer regulations -- many of them already concerning how they maintain, manage, and distribute their own platform. So why are all those regulations ok but this one isn't? If we remove all consumer protections and regulations then consumers could still -- as you say -- choose to use a different platform.
You could argue this specific regulation itself is bad -- like you can with all other regulations -- but the concept of regulating a business for the benefit of consumers has long been already decided everywhere in the world.
I don’t have any substantive basis to argue some other regulation versus this one that isn’t an emotional basis as a developer without doing further research, but this regulation has now inadvertently made it a worse experience. To my perception this regulation has gone far deeper than any before defining the “market gatekeepers” and attempting to govern how a company can monetize its own market. Regulations are usually “how a company can sell a product in the free market” not “how a company can monetize the services of its already existing product”. That is a consideration of the consumer during purchasing of the product, or a consideration of the developer when developing for it.
At the minimum, this was a poorly planned and executed regulation as displayed by Apple here.
Digital services revenue didn’t exist in the 19th and if even at all during the end of the 20th century, so this is still a relatively new space in the timescale of government regulation, and is an entirely new type of market.
Financial services, subscriptions, and other service-based commercial relationships pre-date digitalisation by decades. The main differences for digital products are actually items that Apple are rejecting even today: the fact that national borders are disappearing, and that unregulated everything-as-subscription creates neofeudal relationships. Hopefully we'll address that at some point.
You could argue this specific regulation itself is bad -- like you can with all other regulations -- but the concept of regulating a business for the benefit of consumers has long been already decided everywhere in the world.