Hmm. There's also a good video here <redacted>. And as for the name "Doctor Who" [1].
The main issue people have with Cushing is he doesn't fit into the "narrative" as it exists today.
But then, let's look at the Morbius Doctors. They never existed, until The Brain of Morbius (TV story) said that they did. Then The Deadly Assassin (TV story) gave us the "thirteen regeneration limit", making them very problematic. By The Five Doctors (TV story) they have been removed from the Doctor's incarnations forever. And one of the books said they were the faces of Morbius instead. Case closed.
Until The Timeless Children (TV story).
For younger viewers, who can simply say "Haha. He's a human inventor who is actually called Doctor Who! That's totally different to the Gallifreyan Time Lord we all know", people didn't know that at the time.
I could also bring up the Polystyle Publications, Ltd. stories. Which ran for FIFTEEN YEARS. Then, one day, a Virgin Novel said "Those all took place in the Land of Fiction". Was anyone reading those stories from 1964-1979 thinking that? It was clearly NEVER the intention for the Cushing movies to be "fiction set within the Doctor Who Universe". And, for 50-something years, they WEREN'T.