For modern readers we might need an update to the old lie about how it is sweet and fitting to die for an entirely different country than your own. One you have probably never even visited.

Seems a bit like an historically blinkered statement. There's a long history of countries militarily supporting their allies; there's nothing "modern" about this.

Most of the countries in WWI - which this poem is about - entered the war because of existing alliances, not because they were personally affected by the assassination of Archduke Franz Ferdinand.

While the US was indeed attacked by the Japanese in WWII, they could have focused entirely on the PTO and left their allies across the Atlantic to fend for themselves. Instead hundreds of thousands of Americans died liberating Europe.

The Vietnam War was at root the US supporting an allied government in Saigon. Tens of thousands of Americans died for an entirely different country than their own, one they'd likely never been to. A tragedy, but a tragedy that's been in the history books for fifty years now.

The Gulf War was 42 separate countries banding together to liberate Kuwait from an Iraqi invasion. How many of those soldiers had ever even thought about Kuwait before being deployed and potentially dying there?

When the US was attacked by Osama Bin Laden, the US invaded Afghanistan in response. Whether or not that was a justifiable decision, at the time dozens of countries lent their support. Their soldiers died for the sake of the US, though in this case maybe some of them had at least visited it.

This isn't an endorsement of dying for someone else's country (or even one's own); just an observation that it was normal even when this poem was written, hardly modern and no need for an "update" (perhaps just an expansion of the original). I also don't want this to come across as a defense of the US or Israeli action in Iran, which I assume is what you're referring to, so I'll be explicit about my position on this: the Iranian regime may be unquestionably awful, but not only is this attack illegal domestically (in the US) and internationally, I have extraordinarily little faith that either Netanyahu's Israel or Trump's US are going to handle this war or its aftermath well, and I'm terrified about the chaos that's likely to unfold over the coming months and years.

But: this sort of thing is precisely why Israelis/Zionists/Jews often view criticisms of Israel as anti-semitic. Things that have long been considered totally normal - military alliances, in this instance - are suddenly treated as novel and uniquely awful when Israel is involved. So their question becomes, "what's unique about Israel that makes people treat us differently", and then they look at their status as the only ethnically Jewish state and the history of how the world has treated Jews and derive themselves an answer. Especially when the complaint is rooted in an age old anti-semitic trope - “Jews secretly control the world” - just with “Jews” swapped out for “Israel”.