Too bad those cases don’t have anything in common. It’s logical to complain about what Microsoft did while claiming Apple hasn’t done anything wrong. Both points are true.
Nothing at all in common, huh?
Computer technology company builds upon some of its previous industry-leading products in order to build a new operating system platform, bringing technological improvements into the mainstream and building a strong third-party "ecosystem" in the process. Through aggressive marketing, strategic business decisions, said company quickly becomes such a dominant player in its industry that they wield essentially complete control over both customers and vendors.
Said company then uses that dominant position to force third-party developers and OEMs into one-sided contracts designed to further entrench their dominant position and restrict competition. Said company also reserves certain platform functionality (via undocumented or privileged APIs, for example) to give technical advantages to their own add-on ancillary software products (most notably, its web browser platform and the cloud services it provides) over those products and services provided by competitors. In other words, using a near-monopoly position in one market in order to entrench a near-monopoly position in another.
There is, of course, a "competitor" of sorts in both of these scenarios, but that competitor is neither strong enough or diversified enough to provide any real meaningful competition and switching costs between the two "competitors" are very high. That is, when they are actually competitors - turns out they are actually closer to "frienemies" than competitors, as one company happens to be one of the largest third-party software and services providers to the other company's platform.
You could read this narrative in the context of IBM in the 60s, Microsoft in the 90's, or Apple today. There is so much overlap that the cases differ mainly in the names of the parties involved.