I still say it would be ironic if they were made of iron. But I don't see how that relates to this strip. I've had days like this. In fact... once, I had a day exactly like this. Then, out of the blue, I was also laid off.
I do believe this well illustrates the phenomenon of change being error to one, but truth to another. It turns out you, then, that you can both be right about Irony, as there are no absolutes. Each of you is individually correct and God doesn't give us an official definition of irony.
Your definition is an island. There are many tipes of irony. You've just limited yourself to the dramatic irony. Stricto sensu, in spanish irony is the rhethorical figure. Everything else is an elaboration over that.