Earlier quoted context omitted.
There will also always be someone else to do the work if you don't. Some people just like to eat.
Just because someone is willing to, say, torture a rat, I should be the one to do it? That's a non-sequitur.
However using that as an example, there are people who work as vermin exterminators, or people who work in labs that have to euthanise lab mice. They probably don't enjoy it, but when there's a need for something you'll find someone to do it.