Wrong. GOMAXPROCS defaults to the number of logical CPUs, IIRC since version 1.5. For example, I have four cores with 2 threads each, so goroutines will be executed on up to 8 threads unless I set GOMAXPROCS to something else or the application explicitly changes it using the runtime package.
And sure, you'll really have the same problems, but IMO channels and goroutines minimize the friction of implementing thread safe programs using CSP. GP seems a bit optimistic, agreed, but I think that there is at least some substance to the idea that go makes it easier to correctly utilize multiple cores.
GOMAXPROCS defaults to number of cores.
Prove it by replacing Sleep in your example with some number crunching, and show how it scales with the number of cores in your CPU.
Running the following code.
https://play.golang.org/p/k_rRxNAyb0i
I can assure you that go runs across all processors by default.
https://docs.google.com/document/d/1At2Ls5_fhJQ59kDK2DFVhFu3...
Once you execute truly on multiple CPU cores (by increasing GOMAXPROCS), you'll be having the same kind of race conditions in Go as in any other imperative language (inb4 Rust Evangelism Strike Force saying "except Rust").