It is a simplistic but very ironic claim.

One of the main problems with the existing social net is that it comes with "economic cliffs" where making a little more is not to your economic advantage. And then people who make the rational decision are seen as "lazy".

For a real example, my niece had to turn down a job because it paid her $0.20 too much to stay on food stamps. And she couldn't be paid less because it would have broken union rules. So she did the rational thing and turned down the better job. Which meant that her skills and education went underutilized.

One of the big arguments for UBI is that this kind of thing doesn't happen.