If you want Apple then an alternative will indeed not help you. If you don't want Android then the alternative provides an opportunity not to be forced into Android.
I disagree. The original quote: "I really don't want to be forced to buy an Android phone". One can interpret it in a way that the person does not want to be forced into Android as the only alternative to Apple. In this case, my comment should be helpful.
Does this sentence change the meaning? The OP did not say they wanted Apple. They said they didn't want to be forced into Android. Of course, without Apple, in the absence of any other alternatives, you are forced into Android.
No, it doesn't. The OP never said they wanted Apple. But without Apple you are forced into Android (because there's no other obvious choice) and this seems to be the problem.
They might also choose Apple, since otherwise it would be Android (i.e., even worse). Apple has a lot of drawbacks too after all. This is not what I would consider "wanting", it's a forced choice (just like choosing Android when Apple is "stopped" would be).
There are always a finite number of platforms to choose from and they all always have drawbacks so any choice of platform can be arbitrarily deemed ‘forced’ by this logic.
The distinction therefore has no meaning, and doesn’t change the implication that the OP wanted Apple.
Duopoly is not the same as "a finite number of platforms to choose". Duopoly means both companies can restrict the rights of users and stay in business, despite the users may not like them.