I think the list is more "What is the most fun right now.", they say "Here are the 15 best strategy games that I think you should all play right now." I love command and conquer but I don't think it has aged as well as some other titles.
Nothing wrong with lists of the most important titles, I just don't think this is that kind of list.
He is right, you know. The title of the article says "The best strategy games on PC" so i think C&C quialifies. Certainly not all of them are great and some have dated gfx and gameplay but the one i would definitely put on this list, and the best in the series, is C&C 3. Great gfx, gameplay, 3 playable factions, awesome superweapons and ALIENS that invade teh Earth. What more could you want in a sci-fi RTS?