Phones are ubiquitous, and the vast majority of businesses have a Compelling Reason to have a presence on these devices. Allowing two companies to make any decision they want regarding what nearly every non-trivial business Can and Can Not Do, is the very definition of anti-competitiveness.
When you are a monopoly and you can influence other businesses in such an overarching way, it is Extremely Appropriate that you have to follow a Different Set of Rules than other people, rules that are more closely regulated to ensure that you are not abusing your position