For the same reason Lapid as Finance Minister has curtailed child support for large families. His voters – largely left wing, bourgeois Tel Avivians devoted to their Labrador retrievers and 4-wheel drive jeeps – are getting satisfaction just seeing the Haredim squirm. They—as a class and as individuals—perceive Haredim and Arabs as “the other,” and want them to hurt. That’s why they voted for Yair Lapid, just as they had done his late father, Tommy Lapid.
The other reason is that, as it is becoming clearer that Yair Lapid is not God’s gift to the Israeli economy (he’s really no gift at all) – the thinking is, if he stays in office another 3 or 4 years, the fate of Yesh Atid would be just like Kadima and all the other “centrist” parties that have sprouted in the wedge between Likud and Labor: they would shrink to 1 or 2 MKs.
Yesh Atid is like the Woody Allen shark metaphor from Annie Hall: “A relationship, I think, is like a shark, you know? It has to constantly move forward or it dies. And I think what we got on our hands is a dead shark.”
Yesh Atid has to constantly be running to the Knesset, because it is not good at all at governing. And as long as they keep running, there’s a chance no one would notice.