The question is whether there's (1) something they can do that's more valuable than watching TV and (2) some reasonable way we can motivate them to do so.
If (1) and if a lower BI is an effective way of motivating that behavior, then that's a good argument for a lower BI. It doesn't follow that the optimal level is zero. I don't expect the number that would stay home and collect their $1 of basic income would be substantially greater than the number that currently stay home and collect their $0.
Which one of us is wrong? Which one of us will be wrong in the future, as more and more jobs can be automated and thus disappear while the amount of people on this planet keeps increasing?
Just remember that the future is now.
Say a policy makes 200 million people better off in some virtuous manner but creates 10 million free loaders. Is that a horrible policy? Say the value of the virtuous benefit is 10x the cost of the free loading?
However, the point of the article here is to assume that millions will be "free loaders" no matter what we do because their labor is unnecessary.