I agree with you that what that guy said was stupid, but analogies are 100% arguments. They aren't always good ones (case in point above), but they are definitely arguments.
Any time a scientist does an experiment on a lab rat and extrapolates that it will work for humans, that is an argument from analogy. Any time you use an analogy to illustrate a point, that is an argument from analogy.
Edit: Man, Reddit is ridiculous. Argument from Analogy is an incredibly common and useful form of inductive reasoning. There is even a Wikipedia article about it. Here's an article from Stanford showing how it was even an argument in Aristotle's time. Here is a tutorial from the University of Hong Kong about it. Even some guy named Martin the Wizard knows about it. Here's like a class thing from Duke about it. Here is a David Angler essay on it.
C'mon people, this is all first page of Google stuff. Get it together, Reddit.