As far as I understand co-routines help don't really help with memory shared across go-routines. They only help in the fact you need to manage spawning and joining threads, making it easier to do stuff in parallel. But they don't provide thread-safety.

edit: I suppose you don't get segfaults or buffer overflows and the sort in go for accessing memory in a parallel context, you get recoverable panics. But that is still not really thread safety in my opinion, it is memory safety.

The language also does not support goroutines, locks, or channels, except through using the C threading libraries.

(I think the original author meant type safety when they made that statement. Though it still doesn't make all that much sense to me)