Hmm, so is it "false prudishness" or actual prudishness? :)

You missed the part where I said it is *not* being *used* as a euphemism (though I understand why it may sound that way to you)? The true euphemism is "darn"! "Dang" just has a special flavor to it. (Speaking in the present, not historically.) The same person may say (and excuse my prudishness for apologizing for the following language!:) "Dang, that bitch is fuckin' hot!"

I realize the toilet thing was already discussed here, though it was maybe years ago so:

"Bathroom" is used for both home facilities and public ones. I see it as more a case of using the same word for the "same" thing. I agree that it is euphemistic, but so is "toilet", to an extent. Bathrooms in public contain toilets, urinals, and sinks for washing. You might go their to blow your nose, for example. The lack of any "bath" in public leads the change, in official language, to "restroom"!
In Canada (or some parts at least) it's a "washroom."
In North India, it's a "bathroom" (using English loan word)...or sometimes "washroom" (where Canadians have had their influence), and also "toilet!" However, in Hindi-Urdu it is "ghusal-khaana," literally "bathroom" - except in some rustic areas, where (in coarse Punjabi for example) it is "TaTTiaan" = "shitters". I recall once asking, on behalf of a female fellow traveler in Pakistan: "oe, zanaanian diaan tattian kithe hagiaan ne?" - "Yo, where are the ladies' shitters?" It felt kind of silly, given my "sahib" status!
A "public toilet" seems to me to be the *official* term, in Europe, for something that generally does not exist in the USA...it's like the yard vs. garden thing. And "toilet" shortens that.
In short: the reading of the level of cultural prudishness from these terms seem premature to me.

Indeed, since everyone knows what "bathroom" is, and what one does there, it no longer (if it ever did) functions as much of a euphemism - it's just the word one uses. Now: Euphemisms are:
1) Go to the library
2) Go to my office
3) Pay the water bill
4) Go to download some stuff (cyber-euphemism)
:D