Clearly Apple wants to make money. The only argument being made is that some customers choose the walled garden because they want a telephone, not a part-time job keeping the weeds at bay. As you say, that's (a component of) what they are selling, and they do it because it sells (long-term, in their estimation).
The number of customers who chose an iPhone because it only lets them buy apps from Apple is a tiny fraction of the number of people who bought the device as a fashion accessory. What a strange thing to want. It makes little sense to think that Apple is catering to the tiny former group instead of simply extracting as much money as it can out of the latter group.
Clearly Apple wants to make money. The only argument being made is that some customers choose the walled garden because they want a telephone, not a part-time job keeping the weeds at bay. As you say, that's (a component of) what they are selling, and they do it because it sells (long-term, in their estimation).