This is an absurd statement. Israel has been killing innocent people in the region since it was created. Iran is right to stand up to them. Bonus points that as an American they're also standing up for me against the Zionists who manipulate my government and steal my money.
We are aligned against Zionism. Few countries are willing to stand up to Israel and Iran is #1 in that regard. Iran is the only country fighting the people bribing and blackmailing my government, stripping my rights and stealing my money.
The chant, as officially translated by the government itself [1] means "Down with the USA". "Death to" is a purposeful (literal) mistranslation to make it sound like it's a genocidal statement.
Is that to say the Islamic Republic of Iran don't necessarily want to eradicate the USA but merely want to see its downfall? I don't have much sympathy for that; it's not like there's some more liberal, more democratic, alternative superpower waiting in the wings.