In my opinion, it's a ridiculous question but how would you answer it? I've encountered, or thought up myself, some answers which I'll try to lay out below. I'm interested to hear other answers, or whatever else you have to say. What do you think?
#1 Most people expound the labor theory of value stuff. A person intuitively feels exploited and tries to quantify that in terms of wages and financial valuations of whatever outputs result from the processes they're associated with. They presume the supply & demand of economic orthodoxy will work in their favor if they refuse to work or threaten not to.
#2 “Bullshit jobs”. Some people notice the fact that very little human input is required to produce what is actually needed for people to live, largely due to labor-saving technological advancements. I expect they (rightly) feel indignant that their limited time on earth is being wasted in whatever bullshit job they have, making widgets or filling out forms or whatever it is that they do merely for the sake of receiving wages, and so they “don't want to work”.
#3 I once heard a sage best sum up another perspective in the words: “If you are subject to the approval of other people, then you have a social ego and therefore no selfhood and that is why you have all these problems in your life”. People don't like having a bunch of problems in their lives. Forming and maintaining a social ego is exhausting. It is obvious that work is a major way someone might be made “subject to the approval of other people” and so they “don't want to work”, and it's perfectly right and understandable that they wouldn't.
#4 Anti-natalists are upset at having been born into the scenario described by the aforementioned sage, but personally I think they are misidentifying a manufactured circumstance as a fact of reality, and I'll come back to that.
#5 There is a common thread running through all these perspectives. We treat labor and money like they're privately owned physical commodities (when they're not) and we're trading them in the fashion of barter. Doing that serves as a secondary justification (proof & evidence) that we are entiteled to be included in society. I say secondary because your mere existence makes you a component part of society and the world, and you are standing on the shoulders of your ancestors, who were also that, and were also due the same entitlements even before any other contributions. Moreover, even were neither of those facts true, the anti-natalists are correct in identifying that you have been thrust of necessity and according to the will of others into the circumstance of your existence.
That those circumstances be coercive, conducive to centralization and repressive is only justifiable according to those whom believe the notion, for some reason or other, that coercion, centralization and repression are all actually good things which mankind must be subjected to. Of course, they're wrong and just coping (with their own existential anxiety, at others' expense), the “proof & evidence” of which is that man increasingly chafes under this notion, “doesn't want to work”, and making him live according to it becomes a more drastic endeavor over time.