They, in turn, would point to America's support of (and promotion of) the Saudi regime and its repulsive ideology of Sunni Wahabbism.
Russia also has very good relations with Saudi Arabia.
For example: “Russia and Saudi Arabia Reach $10 Billion Arms Deal”
https://uawire.org/news/russia-and-saudi-arabia-reach-10-billion-arms-deal
“They, in turn, would point to America’s support of (and promotion of) the Saudi regime and its repulsive ideology of Sunni Wahabbism.”
You are missing the point. The Iranians are threatening America with missile launched nuclear bombs.
And Russia is helping them build those things.
Someone who helps your deadliest enemy arm himself and improve his ability to attack you, is also an enemy.
The Saudis are nasty, but they are not an existential threat to bomb Russia. They don’t even have a nuclear program, or a missile program.