---deliberately saving a copy to wayback or equivalent is tougher, but if a website is actively endangered, that's a little bit different than just doing it to everything automatically, so I would at least consider it.

I'm going to be a bit firmer here: it's a war situation. It's ethical to do whatever you can to save knowledge and history from the depredations of war or dictatorships. Ownership and legality didn't matter when the Nazis were coming to loot the treasures of the Louvre; stealing artwork away and hiding it from them was more important. If you can snatch a book from a bonfire, you've done the right thing, even if it wasn't your book.