I understand not wanting to do fireworks on Shabbat, just as megillah reading, matanot la'evyonim, etc., are moved to Friday or Sunday when Shushan Purim (15 Adar) falls on Shabbat (like this year). But even in that case, the liturgical aspects of Purim (al hanisim, vayavo
Also, among those who observe mourning practices during sefirat ha'omer (which I don't, so this is a moot point for me), many of them suspend these practices on Yom Ha'atzma'ut. Therefore, actions that would otherwise have been forbidden to them (i.e. anything they don't do during sefirah) were considered to be permitted on Thursday 3 Iyar, because the Knesset decided that this was the date of Yom Ha'atzma'ut. What is the possible logic behind letting the secular Knesset rule on matters of issur v'hetter?
Once again the ends of the spectrum meet!