This is one reason that if you see some information like this a screen grab and text grab should be done so there is a backup. If you actually post something about it when you do the grab there will also be a time stamped undeniable post recording it.
I know hindsight is 20/20. It's easy to talk about doing this after the fact.
There is also the internet archive and the wayback machine which is a boon for saving pages they delete or edit to hide stuff.
Yep those are great as long as the catch and archive it. If they do then you're in good shape and don't have to do anything extra. They don't archive everything so if you think it is important snag what you can and point it out to other people using some fashion they can't erase.