There are people within the internet archive whose politics is so strong that I have said in private since 2016 that I have concerns they are a risk to the neutrality of the project. I am not going to mention their name to avoid a flamewar but that name will be mentioned more by others if they decide to remove more content.
https://en.wikipedia.org/wiki/Four_Horsemen_of_the_Infocalyp...
Apt would be, should publishers have the right not to publish material like Mein Kampf, if they so choose, or does "free speech" now mean that all publishers must be forced to publish everything, however objectionable, if legal?
The remove part was done already. They are not on the internet anymore. It was removed from Internet Archive because it contains some inconvenient information about DIY HRT to minors and other accusations.
second: if it's true they have to notify it; and explain how researchers can access to this material.