> "at the moment" implies that Go would need to change for that statement to change

I agree that "at the moment" could imply that Go would need to change for that statement to change, but I think it could also imply that "effectively/practically" could change as well since "effectively/practically" in this context implies a particular state of knowledge about known exploits (i.e., that there are none). If someone releases a practical data race exploit for real-world Go codebases tomorrow, "effectively/practically" would no longer hold, and therefore the statement would no longer hold despite Go not changing. The representation of the state of knowledge is part of why I suggested the lawyer-y version :P