Earlier quoted context omitted.
Defining Apple as a monopolist on iOS is like calling Ford a monopolist in selling radios in Ford vehicles. No one thinks it’s a violation for Ford to include their own radio (built by a 3rd party like Bose - same as an app) in a Ford truck, and offer you an expensive upgrade to that radio (say also by Olufsen - also like a better App) if you want it. No one demands that Ford allow a different vendor to sell you a co…
And if Ford says that installing a third party radio without their authorization voids your warranty or otherwise makes it impossible to do so, it’s generally accepted to be OK. Don't know where you live, but that is not true in the U. S. "It is generally accepted as" against Federal law.
Companies can say things they know aren’t true, misleading customers. They even often can make it hard for customers who know their rights to exercise those rights.
I think it would be an improvement if such actions were punished harsher and more often.