On another tack. The basic word processor "Bean" in fact can directly edit (in a WYSWYG way) webarchive files. I just figured that as I wouldn't be able to see the javascript in my previously saved file I wouldn't be able to remove it. I have previously regularly used Bean to strip out unhelpful objects from saved web pages. However, it may be best to save a COPY of the webarchive file before editing it with Bean, because it may automatically dump stuff it doesn't like from a page. That may be fine with you, but it may significantly change the layout of the page, such as dropping the entire side menu and site logos!
This was no problem with my saved e-mail page, so instead of using "WebArchive Folderizer" I ONLY opened it with Bean. In order to save the file I had to make a change. That could be adding a single space, but in this case I simply deleted the GMail logo. This made the file size drop from 16KB to 12KB (it may not have removed a full 4 KB from the file, but as the Mac file system operates in increments of 4KB, this is the difference it made, on disk).
I then reopened it in Safari, and lo and behold, no JavaScript!