Fuck that. If anything had happened in Iran before Mosaddegh was overthrown by USA that would constitute a defensible justification for that action, I'm sure you would have told us already. Instead, here's some innuendo. Gosh that chanting is bad.
Also, implicit in your criticism, such as it is, is the notion that the chanting is representational of the Iranian population. It is not; most of the country has lived for long enough under the 'revolutionary' rule of the IRGC that they are actually more disposed towards the West than you might think.
Regardless, you asked why the U.S. was tilted towards Saudi in its conflict with Iran, and I was trying to provide a summary: that is an outgrowth of regional balance-of-power politics as much as anything else.
I wasn't the one who initially asked why USA traditionally favors Saudi over the Ayatollahs, but frankly your response to that query is an exercise in question-begging. They wouldn't chant "death to America" if that chant weren't rhetorically useful. It wouldn't be rhetorically useful if USA hadn't intervened to remove an elected Prime Minister.
And the purpose of this article seems to be to demonstrate that the Americans don't have any clue which side they are on.
The Iranian government has literally been chanting "Death to America" every week since 1979. Our relationship with Saudi is much, much more complex.