Hang on, they mostly agree with each other. I've spoken to Rob Pike a few times and I never heard him call out Perlis as being wrong. On this particular point, Perlis and Pike are both extending an existing idea put forward by Fred Brooks.

Perlis absolutely is not saying the same thing, and as the commenter notes the functional community interpret it in a particularly extreme way.

I would guess Pike is simply wise enough not to get involved in such arguments.