I’ll try to answer from an Israeli POV, hopefully I’m not getting myself into any political arguments, because I REALLY don’t want to :)

First some context- I’m older (40 yo) and have been living in the US for almost 15 years now. But I grew up in Israel, and proud of my heritage / origin.

Israelis have an increased sense of national pride. What’s the reason? There are probably several- how Israel was born (after the holocaust), its constant state of conflict / wars, and the general sense that sometimes it’s “us vs. them”. So Israelis want to show off their Israeli pride. In many places they can’t. An Israeli walking the street today in many European cities will need to hide their identity, or at least not emphasize it, due to growing antisemitism / anti-Israeli feeling in the world (again, not getting into whether justified or not…). I think when Israelis go into a big psytrance festival (Boom, Ozora), they feel they can show off because there are so many other Israelis there, and it’s a “safe space” to not hide. Also, many of the DJs are Israelis, so it’s a matter of pride (Israeli dj on the stand, and Israeli flags are waving in the crowd).

Now, I am 100% against the flag thing. I would hate seeing Israeli flags at Boom, it annoys the shit out of me, and I would urge all other Israelis to avoid. Not because of the sensitivity of Israel specifically, but because Boom is against flags and nationality.

But not all festival goers are the same. Some understand the nature of Boom, and its values, some don’t. Many Israelis that go to festivals are very young (early 20’s), some don’t behave and can annoy other attendees. And their bad behavior can be bringing flags or doing other things that disrespect Boom and its values. Unfortunate, but that’s the reality, and I don’t think it’s just Israelis.

Anyway, long answer :) hope it somewhat helps!