That was a memorable Far Side comic for me because the moment I saw it, I knew what Larson was going for, and how badly he had failed, and how a lot of people would misinterpret the comic. And I was right. Even looking at it now, I just wonder how Larson could not have seen it.
I have a book of his called "The Pre-History of The Far Side" which has a section on some of the various controversies that he's managed to stir up over the years, most of them due to people misunderstanding the comic, but most of those, admittedly, were at least partially his fault. It's a pretty good read, and funny, too.