Millennial Millie presented more or less this argument to Earthling Ed as justification for animal agriculture, but this sort of argument is presented repeatedly in some imagined scenario
This has nothing to do with the optional killing of animals for your own entertainment. The question is: have you ever been in a situation in your life where you have had to kill and eat an animal and feed to it a loved one or else you would starve? If you're not in that scenario, then this argument doesn't apply.
This position is that necessity in some hypothetical scenario justifies anything once that necessity is gone. But the first killing in self-defense doesn't justify all killing all the time, so this argument just isn't a cogent defense. We have no problem identifying the problems with an argument like this in any other context "Oh sorry I stole your car for a joyride... but you know, I could have been driving someone to the hospital in some strange parallel universe. What about that? Did you think of that?!". It's comical when the same framing is used in a context that isn't as easy and convenient.
The funniest answer is just "Why would I kill an animal when I can pick up a vegan pizza from a place 5 minutes from my house". "Ok, but, I mean what if you were on a desert island?". "Oh then I would wait until the director yelled "cut" and we were done filming then order them something to eat from my phone.". "No I mean you're not acting in a movie." "Oh am I then in a TV show?... because there are a lot of vegan joints in southern California where those are usually filmed...".
Just disingenuously head for the door in any thought experiment. Did they put you on a glacier with only a seal to eat? Screw it, you put aliens in a flying saucer there with you.