It's fine. It's still message passing and it's obvious they refer to Go flavored CSP style message passing whenever they talk about it, not anything else.
(I've been using Go since it was released and like the language.)
Go tried CSP in the beginning but in CSP the 'sequential process' preempts only on blocking (IO) or until finished.
Also message passing is just that. You can't reach out and modify a message after you have posted it, IRL. This means messages are 'safe' to use concurrently since they are copies. That, in conjuction with strict CSP ssemantics (processes always run to completion with no preemptive cooperation) gets you 'safe concurrency' at the price of performance and at scale 'reasoning' about what is happening.
So, the practical decisions were (a) honors system message passing via references, (b) preemption at IO and elsewhere, and (c) introduction of mutex, etc. to fall back to [more performant] 'light weight threads' and 'locks' paradigm.
