It might not be legally binding, but I don't think that was the point. (Okay, after reading the original essay, it clearly wasn't the point at all.) But what about the implications for non-download software? After all, if you buy software in a box -- the fabled "Brik N. More-Tor" seems to be a common source -- you can't even see the EULA until you open the box, and if the terms are unacceptable, too bad. A lot of retailers won't accept opened returns. So why not return absurdity for absurdity by having your beloved pet accept the terms? Everyone's happy...ish.
Now, if your pet figures out how to work the computer on a more complex level, such as pirating software (with a cute little skull-and-crossbones hat to match), or typing in a very precise string of characters followed by delete -- THEN I'd worry.