Most comments (and the article) missed the point.
Opera's complaint was that Microsoft had an unfair advantage with browsers, as it bundled IE with Windows (which IS a monopoly), ensuring that all computers that shipped with Windows had it - and couldn't remove it.
William Gates III argued to the Congress that IE couldn't be removed from Windows without compromising the OS' integrity (he obviously had his fingers crossed behind his back when he said that). Thus, IE6 from 2001 to 2014 (the most loathed, buggy, underdeveloped browser in computer history, managing to beat even Netscape 4).
Shipping other browsers with Win7 wasn't possible, from a license point of view: several include GPL code, which forbid shipping with non-GPL code. Moreover, there is the OEM support, that would require either Microsoft or its OEMs to support the software. But, a ballot screen is nothing more than a dumb piece of script that can download an XML file from a Web location, said XML file contains a description and a download location for a list of browsers - like IE 7 does to offer you several search engines for your search box.
If Win7 shipped with this type of script, support would be exceedingly simple: an OEM would 'merely' have to support said XML file somewhere on their server. The actual browsers, being third-party tools, wouldn't have to be supported.
You have to understand one thing: in the EU, other browsers like Firefox have more than the 20% market share US tools report; it stands between 25 and 45% depending on countries. So, OEMs find themselves 'forced' to know about it and support it with their tools, their tech support often recommend you install at least Firefox, for example. However, since IE is still installed, security breaches and all, it still gives everybody headaches - IE and non-IE users alike.
The EC asked Microsoft to stop bundling IE with Windows; Microsoft complied somewhat with Win7's beta 2 (IE is neutralized, not removed). So as not to penalize users, the EC then asked Microsoft to add a simple ballot screen allowing the user to install his or her browser of choice. Microsoft refused point blank and completely removed IE's GUI (the html and jscript engines are still there).
Now, what could that mean? Well OEMs may either install IE or any other browser instead - or add a ballot screen of their own. Or (banish the thought) install their own branded IE version.
Wait. They are already doing that.
The Mac OS X/Linux controversy: OS X ships with Safari. No uninstall option is given for it. Apple could thus face the same problem MS did - if they ever attain monopoly status. They didn't, so they can't be accused of making use of monopolistic position to gain an unfair advantage. Linux is even easier: not only you can't accuse desktop Linux of being a monopoly, but you ALREADY can remove the browser and replace it. Debian (at least) ships without Firefox but Iceweasel instead.