I don't think the parent here is talking about whether the language is static/dynamic.
The point is that most REST calls are wrapped in a statically 'dispatched' function call.
So in most cases you'd do something like:
let foo = () => http.GET('/foo');
.
.
.
foo() //foo is statically dispatched in the source code here
It seems like "RPC" is being used pretty loosely in this thread. Whether foo in your example is RPC or not depends on its signature, if it attempts to synchronously return the response from the server, then it is RPC, if it just returns a Promise then it isn't.
So in most cases you'd do something like: