Well it's intel's compiler,they made it the way it is.Software companies can use other compilers out there,but most firms prefer intel's since it gives the best performance on intel's chips(which are the most spread CPUs on the market).
It would be nice to see a Linux open source test bench application suit(like the one Phoronix use),which could be compiled with best compilers out there for both intel and AMD.Crippling the AMD to less optimized SSE path(as shown before in my previous post) has serious performance effects on AMD's chips.I wonder what paths are used by such apps and games as Lost Planet,FutureMark Vantage,Cinebench etc. when you run them with non-intel CPUID.