Not only do you jump to an insane straw man.

It wasn’t an insane strawman though? It was literally the argument they made. Something has to die for you to eat, therefore it doesn’t matter how many things you kill or how necessary those deaths are. The fact that you must kill something absolves you of any guilt for any amount of killing, is the ridiculous argument the person made (and which carnists often make) which we are making fun of for being obviously evil and wrong.

Or the number of days since their birth? That’s the simpler explanation.

“Those apples are numbered” = “we know how many apples there are right now”

No, that does not make equal literal sense to what I said. Because days that are in the past are gone, we don’t have them anymore. We refer to moving through time as “killing” time or as “losing” time, in English we don’t tend to think of the past as something we currently have. The future is something we have or will have, the past is something we had and no longer have.

It means that you can place a specific number on the number of days left in a person’s life? I’m not sure I understand the question because the meaning of this one is pretty easy to see. Normally it is unclear when your death will be, but if someone tells you that your days are numbered they are implying that they possess the exact knowledge of what number of days you have left to live. They don’t usually mean that literally but the literal meaning is pretty clear.