If a foreign crowd started chanting at a music festival, "Death death to the RAF" then I would think: Why are you saying that about my country and my fellow citizens? And would you be hostile to me? These are natural, quite obvious questions. How do you think a Jew would feel at Glastonbury? People often DO associate citizens with their government - even from the past!
I was talking to a guy on holiday last month from Oman (who part owns Uber) and one of the first things he brought up was Britain as a coloniser. Er, what? I had to remind him that while Britain sought to abolish slavery, Oman kept it up until 1970. These fools don't know anything about history.
So why is "Death death to the IDF" a problem? Well it's a chant that stops just short of "Death death to the Jews". That would be too obvious, wouldn't it. The IDF is made up almost entirely of Jews.
We know antisemites use coded language like "Zionists", "Israeli government", "IDF" as euphemisms to attack Jews without openly saying it.
Have you ever heard the chant “Death to the IRGC” (Iran’s Islamic Revolutionary Guard Corps), “Death to Hamas,” “Death to Assad’s army,” or “Death to the Russian military,” despite those groups committing well-documented atrocities? Again, the Jews get special treatment.
And calling death for a specific group encourages real life violence! We have already seen this play out.