You just cant compare *nix and Windows on that base.
Lets make environment "equal" before compare.
Lets take a dumbass user name number 1, Joe.
Install Windows:
Put cd on drive--> next-->next-->next......>finish. Its done
Lets take a dumbass user name number 2, Jack.
Linux distribution:
Put cd on drive--> next-->next-->next......>finish. Its done

Lets compare Joe' pc and Jack' pc. Can you see a difference except OS? I cant. Both are crap installations with tons of vulnerability. I bet that Joe will use Administrator as primary logon (without password) and Jack will use root. And both will install all cratp that comes on CD, doesnt matter if they need those or not.

Dont tell about a lot of utilities and so on. ITS NOT A SECURITY ISSUE. (BTW most of those free utils can be installed on Windows nowadays).

If you do the same thing with two expert (Windows expert and one Linux expert) both will be secure enough.

When you need to deploy security on *nix, its harder as deploying it on Windows.

I agree with the report. Its (nowadays) a matter of the "quality" of vulnerabilities.

MS: respond faster to new ones (that is true). But new holes on MS software use to be to critical. They DO need to take more care about code quality. (and the are doing that). MS is also preparing to defend itself when d-zero attacks appear.
*NIX: slow response but the flaws are usually hard to exploit on a short time. But the D-Zero flaws come, *NIX companies will have a bad time with the users.

Im not a fan of Windows , nor *NIX. I use to deploy enviroments with both. Both has pros and cons. On some enviroments, one is ALWAYS better than the other one.

BTW, im a Mainframe borned System Programmer, so every pc platform looks "weak" for me