I like the clean margins and typography there.
(Click/tap the cup in the lower right corner if you visit outside opening hours) :-)
(e.g., https://www.irs.gov/payments/view-your-tax-account see the "Hours of availability" section)
What makes you ask this question? Is it privilege? Ignorance?
We aren't talking about a silly pet project. We're talking about important government websites that need to be available to every citizen of the US, regardless of their work schedules and obligations. Artificially restricting the hours is insane.
Updates make some sense, but most situations I see things of that sort it's "X may be down for maintenance during these hours", which it usually isn't most of the time in reality.
https://www.bhphotovideo.com/find/HelpCenter/StoreInfo.jsp
That's a lot more than any other business I can think of, but it might not be a majority depending on how you count:
There is one.
Great take on user interaction and design.
If someone feels this idea seem far-fetched, think about how applications or sites make you feel when it belittles you for mistakes made in an input, dropp all your progress because you followed the misplaced button, or use the ‘cute but sad animated animal mascot’-dark pattern when you want to cancel an account.