Deepfakes are about impersonating the person in the video, fake news is… Well, just someone lying. Signatures are meant to verify the source of information, not the contents of it.

Simple example, we can be nearly 100% confident that the person posting tweets under the Trump account is (atleast authorized by) Trump. Doesnt stop him from lying nor uploading a deepfake video.

Sadly the r/dota2 community doesnt seem to have migrated that much. Which is a shame because everyone from pro players to valve use it as an official means to communicate.