Query: " So the RACES isn't only for Amateurs as trained communicators?"
Response: That's right. It does not have to be. Communicators can come from a variety of backgrounds, not just Amateur Radio. However, to actually operate on the Amateur Radio Service frequencies, a license is required, but experienced non-amateur communicators can be used under the supervision of an appropriate licensee.
That use of non-amateurs on Amateur Radio frequencies really IS NOT what this is all about and it is seldom done, but in an emergency could if needed and handled properly. Rather, it is that participants in an emergency communications unit can handle many non- Amateur communications that are of inestimable value to government.
Part of the changing scene - that so disturbs some Amateurs - is government's reliance on wired systems (say computers) and the jurisdictions government-frequency radios. Yet, there is a place for emergency communications on Amateur Radio bands. However, the fact of life today is that a unit that cannot expand its visions and usefulness beyond the Amateur Radio bands is likely self-limiting and headed for eventual disbanding. Of course there are exceptions, such as in rural areas where government communications systems may be quite limited, making reliance on Amateur Radio frequencies a fact of life in that area.
In today's complex communications arena there are many systems useful in emergencies. A communicator may come from a computer background for instance. Following the Northridge earthquake the CA State OES ACS supplied several computer specialists for communications needs. None of them were licensed Amateurs, but one did later become a licensee. An emergency is no respector of the type of system that may be knocked out of service or need augmentation. There may be a need to support a vital system other than radio, and astute units are well aware of this fact.
One source of trained communicators, for both the ACS and the RACES, is the Civil Air Patrol (CAP). There are many Amateur licensees in the CAP, but holding the Amateur license doesn't in and of itself make them a good communicator. What does lead to becoming a good communicator is the discipline that CAP teaches and requires on its frequencies. Amateur Radio also has its area of discipline training: highly efficient nets, dx operations, emergency nets to name a few. But just rag-chewing (talking at random between licensees) does not mean one is a trained communicator. As has been pointed out, there is need in government emergency communications units for communicators beyond those who just operate radio.