I think the argument isn't that Python code out performs C code, it's that code written by mediocre Python programmers often outperforms code written by mediocre C programmers. C code is fast enough the mediocre programmers get used to letting the language bail them out. Python programmers know that their language is slow and that they have to work around it.

I've encountered this several times in my own career. A co-worker who writes in C will be implementing a process in parallel with my Python implementation. A week later, my O(N) Python code is outperforming my colleagues O(N^3) C code, since I chose a more complex algorithm which is trickier to get right. The C programmer then re-implements my method in C, which would completely trounce my own code, except I've spent that time leaning on BLAS and LAPACK, speeding up my operations again. The C programmer then starts using fast libraries instead of her own code, again beating my old source, only to find that I've now pushed a good chunk of the processing onto the GPU.

Eventually, I will run out of tricks. The final draft of the C code will trounce the final draft of my Python code. However, during most of the creation process, my Python usually out performs their C. Also, a truly talented C programmer would write my colleague's final draft as her first draft, negating every advantage that I had in the process. However, that's not a situation that I'm likely to run into, because places hiring truly talented programmers aren't likely to be hiring me.