Why some websites got removed by the United Nations??

Wondering about this, a website i used to visit since it had a theory of how to make a time machine was purged with a blue image of content removed by united nations, along any information is classified under level 5 security clearance.

Is kinda funny since is like they are proving that building a time machine is possible following the theory presented on the website, sadly got removed from internet by themselves even if it was a small website.