I disagree. The Windows logo is just a cross in a box with multi-colored panels. You can twist, turn, bend, or re-color it considerably before it's unrecognizable. When they've wanted to make their images more dynamic, they've curved the lines. When they've wanted to look more professional they've muted the colors and outlines. It's still clearly a divided four-panel window.

In contrast, Tux seems a bit stuck. It's going to be hard to make him anything but cute and cuddly. A more stylized penguin would look cold and sinister.