They were found using monopolistic tactics to crush Netscape Navigator. Bill Gates et al were the decision makers. The web browser and Internet are a threat to closed proprietary operating systems like Windows and iOS where applications run exclusively rather than cross platform. Windows used to be where most all applications run. Apple iOS now has the same situation and you will notice Apple less and less happy to help applications run in a web browser and will continue to update Safari iOS less. But it was Microsoft that was found guilty in court for monopolistic anticompetitive actions.

I think it's funny now that if you sell an operating system where you want to talk about number of apps on your OS how important it is those apps cannot run on another system. The low hanging fruit of apps that can easily be written as a web app run on every operating system thus giving no advantage to a proprietary operating system and really enable smaller indie developers.

Microsoft is paying for its past sins, Apple is locking you up and being anticompetitive now, Google is ad spamming you, and I guess Facebook.

Everybody is trying to make a buck. Sometimes the DoJ gets involved. See Microsofts recent efforts to get DoJ after Google :)