The mere possibility of tampering with memory is indeed the most dangerous thing that could happen to humanity. Imagine not being able to believe your own memory. In fact we don't have to imagine, I believe I've been subjected to "mass gaslighting" on multiple occasions recently on the internet : some piece of information I'm sure I saw on the internet suddenly completely disappears. Google + Facebook + "right to be…
Unfortunately, I've got news for you, fallible and manipulable memories have been around for a long time. For example, see the research of Elizabeth Loftus: https://en.wikipedia.org/wiki/Elizabeth_Loftus
The really interesting part is that you can create a false memory for someone even while telling them that you are doing it.