Then let me explain, it's simple, Apple is now a monopoly or monopoly-like, and now it needs to share with others. It's too big and has too much influence. This is to the detriment of the population.
It's like copyright laws (well - as intended anyway) - you get your exclusive rights for 20, 25 years, then it needs to be considered public. If something experiences amazing success during that time, the creator and original holder will benefit greatly, but at some point, it is in the public interest to release their works into the wilds.
This is not to take anything from anyone, but the system was designed like this to both benfit society at large, and to give enough benefits to individuals to create new things. I think it's very much fair like that.
Of course in reality copyright law, like most other laws, have been made into a farce, where Disney extends its mickey mouse copyright forever and ever through various tricks and bribes, same for other big brands.
At this point Apple must be considered a quasi monopoly in phones - just like Microsoft once was (and still is in PC operating systems).
It is therefore in the interest of society at large to let other people build on top of the platform. 3rd party app stores are more or less a no brainer.
For example, if I want to create software that runs on people's phones, but the one company that makes half of all phones does not let me, but they also legally and technically prohibit me then that's anti-competitive behavior.
Take the example of Cydia - it is a working app store; why should Apple be allowed to use all sorts of technical tricks to lock them out? I don't think Apple needs to go out of its way to support them - but going out of their way to remove all competition when you are a monopoly is not acceptable.
That's like Microsoft wiping out the competition with Word, by adding intentional incompatibilities with 3rd party apps into the code.
