Windows is always going to be bashed about, partly due to users experience with it and partly because they are in the spotlight so much.
Isn't this the sole reason why Microsoft gets so much stick? I'm sure if the linux source code wasn't available and they where just as big as Microsoft they would be in the exact same position.

It's just a case of preferring the underdog in most cases as far as i can see, and i don't think i need to know much about security to say this.