I'm not discounting everything you said, but don't you think the biggest reason that MS gets nailed with so many virus' is because of the anti-capitalism anarchist that see a large, ubiquitous and for-profit MS as the ultimate incarnation of "the man"?
For whatever reason, Apple is not looked upon with as much loathing and contempt by the nutbag left and therefore isn't as targeted by the hackers as much.
Sure MS makes it easier because of the incestuous relationship between OS and browser (and other MS apps), but a lot of it has to do with MS as the object of hatred in and of itself.
“the biggest reason that MS gets nailed with so many virus’ is because of the anti-capitalism anarchist that see a large, ubiquitous and for-profit MS as the ultimate incarnation of “the man”?”
No, it goes all the way back to the DOS days. Windows was (unlike the Nixes including Apple) originally designed with zero security because it was meant to run on single PCs. Its marketing model was always to allow itself to be cracked and pirated to establish market share.
Now, love them or hate them, but open source and Linux and BSD programmers wouldn’t be caught dead trying to pawn off the crap code Microsoft writes, it is just considered an embarrassment. So the other operating systems simply do not have the same structures built in that allow them to be easily compromised.