I don't understand how it's Google's responsibility to fact-check and police the links it merely indexes (to me, akin to suing a distributor) which is completel

I don't understand how it's Google's responsibility to fact-check and police the links it merely indexes (to me, akin to suing a distributor) which is completely protected first amendment speech. Why didn't the plaintiff simply go after the publisher (the website) and get the false information removed (as well as sue for defamation).