If not on Twitter, they'd send the message out through different means. Twitter is cheap and easy, so why not?
I had an Iranian teacher, here in USA. Despite the calls to violence, its clear that we hate each other's countries, but not each other's peoples.
Well... by and large anyway. I'm sure there are assholes who actually wish death personally on both sides. But there's an understanding of the global political stage. There's still a way to communicate. I think there's a path forward for diplomacy even in these tense times.
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Knowing these things really helps put ideas into context. Ex: Iranians got really pissed off at the movie 300 for example (after all: Iranians see themselves as the Persians. So seeing a bunch of Persians get slaughtered by the "Western-world Greeks" on a big Hollywood movie is not exactly nice to them either...)
These sorts of things are just accepted. Iranians know that the Persians are by-and-large demonized by the history books that our culture teaches, and we know the same for their side. These conflicts and tensions have been around for literally centuries and millennia.
[1] https://unintendedconsequenc.es/thunderbolt-on-its-trial/
I'm also literally younger than the events which spawned the "Death to America" meme... and I recognize that my similarly aged peers don't give a crap about history.
At this point, the saber-rattling on both sides is just typical American / Iranian foreign policy. It gets crazy because nukes are involved now, but that's life.
Hopefully, my knowledge of history will better inform me over whether or not the actions of my country (and leaders) are doing the right thing. But... I'm not expecting any of the saber-rattling to end in my lifetime.
During the Arab Spring, it looked like doing this stuff online was a net positive for human rights. We've seen the other side, too... and now it seems that Twitter doesn't want to facilitate the escalation of national conflict.