It's not "your own platform", that's what the article gets wrong. The entire purpose of SGX is that it's my platform (that I can control/be assured that you can't), running on your hardware.
It's not my platform either, it's Intel's platform and I'm simply trusting them as to what code is running on SGX. Might as well trust Amazon or any other cloud provider.
Except then you trust Amazon and Intel, not just Amazon (presuming you run on x86). The nice thing about SGX is that you don't need to trust the whole cloud provider software stack.