They haven’t considered that healthier people will be able to work more and probably want to work into older age longer too. So you may see more people move from being out of work to being in work, or those working part time working for more hours. And probably taking less sick leave too. And saving the NHS money too due to being healthier.
But the DM isn’t about a reasoned argument and is just about getting the clicks, and blaming WLI is one of their current favourites.