The chocolate bar in this analogy is given to people right now in the form of conditional welfare. You appear to be arguing that it should not have a chocolate bar to give because it comes from taxpayers, so let's operate from that premise.
Okay, so no more government chocolate. This has fixed the incentive problem because people get nothing whatsoever, but they do get chocolate in reward for working. All is good, right? Well, as a result, people with no chocolate start the Great Chocolate Riots. Buildings and businesses go up in flames. Crime goes way up. Healthcare premiums, yours included, skyrocket. The guillotines come out and people with all the chocolate start losing their heads. It turns out that people just really love chocolate, to the point of needing chocolate, so it's a really REALLY bad idea to withhold it, however fair that may sound to those with all the chocolate.
That's the reality-based argument that we will never exist in a world where taxes don't exist, but what we absolutely can do is make sure those taxes go back to people as cash so that everyone can make their own decisions within markets instead of letting governments set conditions to control people and distort markets.
As for other fairness arguments, please look through my other Steemit posts, as I've already written a few blogs here along those lines. Thanks!
If the goal is for the government return cash to the people, why tax them in the first place.
And do you really expect us to believe that instead of working for a living, people will riot and society will end? I think you are proven wrong every day, when millions of people get up, go to work, and are happy to do so.
A flat tax combined with a basic income would be extremely simple to administrate. It would save money and shrink government. If we instead decided to only tax people if they earned enough, that would require calculating everyone's income which would require government workers, and it would also require targeted welfare which punishes people for working via withdrawal of benefits in reward for working.
As for thinking everyone will do nothing, I don't know what you're talking about. People sell their labor in the labor market because they have no other choice, unless they are born rich that is, they have a choice. Only one third of the labor market in the US is engaged by their work. Do you think that is evidence people love what they do?
I don't at all think people are lazy, nor do I think people should be forced to work involuntarily. I think work should be fully voluntary, and that the work people do is what they choose to do, for enough money to get them to voluntarily do it, or for no money because their basic living expenses are already met.
Why have an income tax at all? It should not be mine or the governments business as to how much you earn. Yes, even rich people work. Try not to justify programs with jealousy. People have to work to eat, nothing changes that, not even printing money out of thin air. Without products being first produced, they cannot be consumed, no matter how much Zimbabwe money you have.