When you register a say message it must be exactly that. If you do register_clcmd("say hello", ...) then it will only be called when you "say hello" and not when you "say hello how are you". It must be exact.
To provide arguments you must register only "say" then read_args() and parse it into the parts that you need (the first part being the .startwar which you need to check to continue then the remaining is your argument).