They don't force it. Amazon, for example, just doesn't want to pay the 30% platform cut. Understandable, but not force, just deterrence.
"just doesn't want to pay"
How unchivalrous of them.
I have no earthly idea what Apple has done to earn 30% of the sale of an eBook by Amazon for the Kindle.
They shouldn’t have to pay for something I buy in a store on their app. Apple doesn’t get to own the entire economy just because they make an operating system
By that token no company is forced to anything.
For instance if the EU or the DOJ were to require Apple to change their policies, we could say Apple isn't forced to do so, as they still can refuse and "just" pay enormous fines until bankruptcy.
I'm not sure what we would call "force" if we take that definition.