Well, bullshit. Every game genre has their pros and cons and NONE are dumber than the other.
I've seen live casts of Starcraft II Masters games and, even though I don't play the game myself, I still find it fascinating. The level of complexity involved in playing a good game of SC2 blows my mind with the amount of crap you have to cope with. There's the build orders, there's the knowledge of which units counter what, there's resource management, there's APM, there's getting the attacks in at the exact right moment, there's keeping your macro up, there's keeping your micro up, there's cheeses, counter cheeses and a whole load of other crap that I'm still hearing about.
As for shooters, sure as far as gameplay goes it's pretty much "shoot thing with other thing". But how about Bioshock? Yeah, you're shooting things, but that's not the point, the point is to draw you into the politics behind it and try to get an understanding of the world. Granted you can get through it without knowing these things, but then you'll be missing out on a huge chunk of the experience.
Another genre people have overlooked. Fighting games. Do you have any idea how much skill it takes to play a side-scrolling fighter against another person? There's a hell of a lot of effort required if you want to master Blazblue, Street Fighter or Marvel VS Capcom. You don't just need to be smart to play them well (learning the combos, counters, behaviors of various characters on the roster, exploits, etc.) but you've also got to be able to form a strategy before the fight based on who you're up against (the character and the player, if the online mode gives you their stats or you've met them before) and you also need to be able to form an organic strategy on the fly with incredible speed. Most of the stuff in fighters can be so fast that you practically need to learn this stuff as second nature to remove the thinking time required to implement the strategies required to keep you at an advantage.
Intelligence isn't just about numbers. You could be intelligent in regards to appreciating narrative, sociology and culture, you could be intelligent in regards to being highly skillful or you could have decent spatial awareness.
Sim and RTS players can be intelligent and complete dumbasses (see WCF on LAG TV for the real dumbasses). But they cannot compare to the different kinds of intelligence required to play other genres.