Seems like small potatoes today, doesn't it?When one takes at face value the extremely simplistic way you stated it, yes, it seems small. But that's not what happened. Microsoft was convicted of using their monopoly position in operating systems to extend their reach into web browsers. Practically speaking, the only consumer operating systems at the time ran on personal computers, either desktops or laptops, and in that market Microsoft held an overwhelming market share. There were no mass market smartphones (there was WinCE, but few I knew had them), Palm Pilots held the PDA market for a short while, but all a drop in the bucket compared to full-blown OSs.
When was the last time you've heard of anti trust litigation because iPhones come with Safari or a whole bunch of Apple services?
Go buy a turnkey Android phone if you don't like it.
What about Google and its software on any and all Android phones?
Go buy an iPhone if you don't like that.
And why can Amazon tie Kindle to its book store and not get sued by competitors?
Apple's iBooks has about everything you'll find on Amazon. Haven't used it, but I'd be surprised if Google Books wasn't close enough.
What were you going to buy computer-wise in 2001? A desktop or laptop that came with Microsoft Windows whether you wanted it or not. That was your practical choice, and the courts found that though it was fine for Microsoft to own the OS market, it was not fine to leverage that into driving Netscape out of business.