They are used to it? The number of users who have JS disabled is already small. The number of those users who lack the technical expertise to enable it as needed (and understand when that is necessary — e.g. with a blank or broken page) is probably many, many times smaller.
And yet most site designers which require javascript turn out to be thoughtful enough to make a note of it rather than leave a completely empty page.
And public sites which absolutely require javascript to do anything turn out to be quite rare.
So there’s no reason to be used to it. “Some buttons don’t work”, yes I do expect i need to allow some JS. “Nothing shows up at all” is usually a network issue.
The noscript tag is something the page would need to use, and does not. Again, page is completely empty (or was, author commented that they fixed it, very nice)