Yom Ha’atzma’ut – Dating the Thing

I cannot understand the calendar as it relates to halacha. I should probably ask someone nicely, but it’s easier to just write about it in the vain hope a reader decides to write in.

As for renegade Jews, no questions. As for religious Jews who ignore the day in terms of halacha, no questions. I get stuck on the overtly Anti-Zionist and the Religio-Nationalists, or Dati Le’umi.

First, the DL. Why does the so-called Central Rabbinate’s moving the date change halacha? In other words, how can you omit Tachnun, so as to prevent the seculars from roasting Treif Rabbanut meat on Shabbos? (Changing the secular Lag Ba’omer so they don’t bonfire on Shabbos presumably has negative halachic consequences, too.)

And those who fast on Yom Ha’atzma’ut. Abroad they actually fast on the day the state was founded: the 5th of Iyar. But here they fast on the ever-moving “official” date. In other words, they fast on the unholiday eve, perhaps Derech Teshuvah, then enjoy a Seudas Leil Yom Tov…

A friend told me it’s similar to the Monday&Thursday fasts (בה”ב). No idea what he means.