Apple is a supplier to software companies (of both hardware and software). They are getting in trouble for messing with other suppliers (of both hardware and software).
To quote the charges in the MS case:
"the U.S. government accused Microsoft of illegally maintaining its monopoly position in the personal computer (PC) market primarily through the legal and technical restrictions it put on the abilities of PC manufacturers (OEMs) and users to uninstall Internet Explorer and use other programs such as Netscape and Java."
Apple in this case:
"Apple is illegally maintaining its monopoly position in the mobile application market primarily through technical restrictions it puts on the abilities of iOS software developers and users to install 3rd party application and programs."
We're essentially playing out a very similar situation, just with the focus on digital goods.