Because they only have a 5% share of the Internet user base, but they feel they can take over our operating systems with their badly written (and untested) software. Check out this story, if not this one.

Ever since formats like m4v, m4a and mp4 have appeared on the Internet, Quicktime 7 and iTunes have ruined all Windows operating systems with stupid Apple bugs. One could say I’m a computer systems expert for more than 15 years now, so I know. I have not seen ANY serious brand that has ever done something as arrogant as this last trick Apple pulls on us with their software. Even MicroSoft never sunk this low, MS at least gives the user a choice, and it doesn’t lie about giving it.
Beware for Quicktime bloathware, it takes over the MP3 MIME type link in your browser, even when you tell it NOT to. Click on any mp3 in your browser and Quicktime will open it. (Who knows what other things this software does without your permission!)
What a load of crap these Apple losers dumped on the net this time! When you change the entries in your registry by hand, in order to set them back to the original associations (that is: to anything but Quicktime), next time you load Quicktime (for some “mov” trailer because all these movie-makers still think Apple Mac equals ‘quality’), it will throw its associations back in your registry! I’d say that qualifies for viral or at least browser hijacking malware.

Apple calls this ‘bugs’. Yeah, right. They know very well how they’re deliberately trying to take over the file associations in MS Windows systems. They should at least have the guts to call their software SlowTime, because they have known about the complaints for months, without doing anything.

And please: Don’t create apple-only media (you’ll’ reach only 5% of all users with your product).
Avoid creating media that are incompatible with other honest software like WinAMP, KMPlayer, etc. Avoid m4v, m4a and mp4. Go with less strict formats like XviD or DivX, and use Ogg Vorbis for audio, skip the hardly developed codecs that don’t work without installing iTunes or Quicktime crap.
Just so you know: Apple is malware now. Stay away from this brand!