If someone quotes a page that you can no longer find, you have a solution. It is the Internet Archive.
If you do not know the Internet Archive (based in San Francisco), you will find it quite a useful research tool. The non-profit stores web pages from around the world. And it keeps old copies of them, so in its Wayback Machine (https://archive.org/web/), you can find what a group or organization had said before they changed their website. Investigative journalists use it to retrace a politicians or business person’s activities when they misquote or present false information. Quite useful.
As of late November, 2020, it says it stores 480 billion web pages. See its story about the Fact Checkers and how they interact with the Internet Archive. Go to https://blog.archive.org/2020/10/30/fact-checks-and-context-for-wayback-machine-pages/