Winnie, a baal berit does not mourn during to Sefira. On Yom HaAtzmaut were are all baalei berit.
LU, the point about chillul Shabbat on Lag b’Omer is that <b>celebrants</b> would be mechallel Shabbat to get to Meron. As for lighitng bonfires being “a very real part of their religious practices”, are stealing wood and making the engihbors sick form smoke inhalation also religious practices?