Because originally Go was designed while Pike and others were waiting on C++ builds and he couldn't grasp why C++ developers don't jump of joy into adopting Go.

> We—Ken, Robert and myself—were C++ programmers when we designed a new language to solve the problems that we thought needed to be solved for the kind of software we wrote. It seems almost paradoxical that other C++ programmers don't seem to care.

https://commandcenter.blogspot.com/2012/06/less-is-exponenti...