Yes. You are right on this.
> But what it's being interpreted as is more like "be excessively prudish and politically correct at all times"
I understand it might seem that way. I believe the original goals were more like "make the AI not spew soft/hard porn on unsuspecting people", and "make the AI not spew hateful bigotry". And we are just not good enough yet at control. But also these things are in some sense arbitrary. They are good goals for someone representing a corporation, which these AIs are very likely going to be employed as (if we ever solve a myriad other problems). They are not necessary the only possible options.
With time and better controls we might make AIs which are subtly flirty while maintaining professional boundaries. Or we might make actual porn AIs, but ones which maintain some other limits. (Like for example generate content about consenting adults without ever deviating into under age material, or describing situations where there is no consent.) But currently we can't even convince our AIs to draw the right number of fingers on people, how do you feel about our chances to teach them much harder concepts like consent? (I know I'm mixing up examples from image and text generation here, but from a certain high level perspective it is all the same.)
So these things you mention are: limitations of our abilities at control, results of a certain kind of expected corporate professionalism, but even more these are safe sandboxes. How do you think we can make the machine not nuke us, if we can't even make it not tell dirty jokes? Not making dirty jokes is not the primary goal. But it is a useful practice to see if we can control these machines. It is one where failure is, while embarrassing, is clearly not existential. We could have chosen a different "goal", for example we could have made an AI which never ever talks about sports! That would have been an equivalent goal. Something hard to achieve to evaluate our efforts against. But it does not mesh that well with the corporate values so we have what we have.
So is this a "there should never be a Vladimir Nabokov in the form of AI allowed to exist"? When people get into saying AI's shouldn't be allowed to produce "X" you're also saying "AI's shouldn't be allowed to have creative vision to engage in sensitive subjects without sounding condescending". "The future should only be filled with very bland and non-offensive characters in fiction."
Did someone took the pen from the writers? Go ahead and write whatever you want.
It was an example of a constraint a company might want to enforce in their AI.