I tried a wide variety of shorter search strings, but - other than results from the last few days with what I suspected was a fake quote - just found what she'd said back in January with very different wording addressing Trump supporters who might want to unfollow her. I'd posted that in reply 20 in that thread.
I just tried the very long string you'd used, and her Feb. 6 post on Threads turned up as the 13th result - with every one of the dozen results before it from just the last few days.
I have a lot less confidence in Google than I'd had yesterday. And it's still mind-boggling that the search string with Rosanne Cash's name in it that I'd used for Google, when copied to Bing got nothing there but results about Rosanne Barr. What have the tech lords done to search???
I've just discovered, too, that the news media and social media aren't nearly as reliable as I'd thought they were at reacting to actual quotes that should get their attention. Despite lots of responses on Threads, and her comments in January getting attention earlier, what she said February 6 was apparently ignored elsewhere until there were suddenly all those social media posts on different platforms starting about April 28. That's a REALLY odd delayed reaction to something posted by a celebrity MAGA was already unhappy with.
I will still look for news stories to try to verify any quote whose source isn't identified. But now I'll have to wonder if some very striking social media post had slipped past everyone who'd normally react to it. (And I'll have a lot less confidence in Google finding it.)