Shouldn't Yahoo! Answers at least be obligated to give us users a reasonable explanation of who or what caused the 'SHUTDOWN!?'?

No

It's a commercial business-decision. The site is not profitable enough, and VERIZON is not willing to invest anything to make it better

Leftists hate diversity of opinion.  Nothing else to understand.

Outside observers say the site is "overrun with far-right conspiratorial garbage."  I think that's accurate, and so it's too expensive now to protect the site from ToS violators.

The amount of people using it doesn't attract advertisers.  That is why  Sheesh so much weapons grade stupidity here, like yours, is the reason not many people come here.  Compare the voting and responses from other Q&A sites.  Some get tens of thousands of votes.  Here it is rare to break 100.

The premier tech company on the planet is OBVIOUSLY wiser that YOU. (Yahoo! - In case you were wondering about 'premier' and planet.') Yahoo! is too powerful to knuckle under ,to CUSTOMERS.

White people keep winning the arguments. That's the real reason.