The most important difference is that the deranged things the Saudis are doing aren't aimed at the West which makes them useful allies, also their current ruler is enacting reforms while Iran is only going backwards
Regarding nationalizing, Egypt had done that and has successfully jumped ship to the western sphere, it's completely possible. Saudi Aramco used to be American owned, you can nationalize with tact
The US' treatment of Cuba is the better example. It's doing none of the things the parent poster listed, yet it's still treated by the US as a pariah state. Uncle Sam doesn't care about how you treat women, or whether you have elections, but he deeply cares about you taking some corporation's stuff 70 years ago.
That is the original sin that can never be atoned for.
(For another example of that, see last night's deranged speech about Venezuela 'stealing' America's oil.)
What do you think about Vietnamese-US relations?
Something makes me think that those aren't the reason for why Iran is everyone's favorite whipping boy in the region.
Nationalizing western assets half a century ago probably has something more to do with why they are treated the way they are.