Does it really come as news to anyone that if Intel wants to show their CPU in best light, they'll use their own compiler?

Caveat emptor.

The bulk of the x86 world uses Microsoft C++ or GCC - end of story.

I disagree. ICC is often use to optimize heavy computation code. As it have a reputation of producing faster code.

I think the parent was talking more about third parties doing benchmarks. If someone (not Intel) uses benchmarking software compiled with ICC, it might report erroneously bad results on an AMD system.

Yup, that was my point. Also, 'caveat emptor' has limits - Intel should at least state that their compiler produces suboptimal code for their competitors' CPUs.