Hard work in society at large is seen as a moral virtue. Rarely are qualifiers added to this when they are it is about the job you hold. For an example: It is bad to work hard if your job is torturing people. What is left out is the dynamic between the workers and the boss.
If you live in a society like the one we currently live in where the worker isn't adequately compensated. You the worker can work hard or not. By working hard you do not achieve your desired outcome: more pay.
People might think working hard is the right thing to do because it benefits society.
But this is not true by working hard while getting little pay you have helped to devalue labor ensuring low pay continues for future generations thus harming society.
To combat this you take an adversarial position to your employer starting unions and doing pro labor things. If you cannot do this you work minimally thus helping set the precedent of low pay = low effort in an attempt to force employers to increase wages if they want to be competitive in the market.
The goal of antiwork then is unions and high wages. If you cannot start a union then do the minimum required at your job to force employers to increase wages if they want hard working workers.
Once adequate pay is achieved and ensured to continue it is good to work hard.
In short hard work is only good when you are not being taken advanyage of and your hard work will not make it easier for people to take advantage of others.
Did I miss anything?