The origin of the word "irony" is the Greek word, "eironeia" meaning "pretended ignorance".
I have a very difficult time imagining how any one can get up in the morning with the thought, "Today I am going to go out and kill something, or as many things as I can." And then again, I guess the clue to an answer is contained in that thought. If that which I am going to kill is simply a thing, I am able to go out and kill it. Therefore, it's ironic.
I wonder which is worse; being ignorant or pretending to be ignorant. I think the answer to that interrogative is fairly discernible.
Another way in which we use the word, irony, is to indicate the "ill-timed or perverse arrival of an event or circumstance that would in itself be desirable" (OED).
I am thinking that the killing by the Sea of four Sealers who are on their way to kill fledgling seals is, indeed, ironic, in more ways than one.