I'm not going to argue the point, here is a good link for starters:
http://secunia.com/advisories/21893/
That's not surprising. The link you provided is not evidence that "Quick Time is full of adware and spyware". Evidently, you are misinformed about the difference between a vulnerability and actual malware.
Well, no wonder. Your link contains absolutely nothing about adware, or spyware.
It describes how a 'carefully crafted H.264, FLC movie, FlashPix file or SGI image can trigger a buffer overflow which may lead to an application crash or arbitrary code execution with the privileges of the user.'
Not surprisingly, the error referenced affects both Mac and PCs, and a security patch is available.
In the grand scheme of things, I reckon this makes it something like (I'll be generous) 10 billion PC security holes to one on the Mac. Which no longer exists.
Bravo!
Yawn.
Now, about that Adware and Spyware?
Not to mention that secunia is known for putting out quantities of FUD.
And notice that every vulnerability (none actually exploited in the wild) has already been fixed.