What is your argument for why denecessitating labor is very bad?

This is certainly the assertion of the capitalist class,

whose well documented behavior clearly conveys that this is not because the elimination of labor is not a source of happiness and freedom to pursue indulgences of every kind.

It is not at all clear that universal life-consuming labor is necessary for a society's stability and sustainability.

The assertion IMO is rooted rather in that it is inconveniently bad for the maintenance of the capitalists' control and primacy,

in as much as those who are occupied with labor, and fearful of losing access to it, are controlled and controllable.