Many things associated with the internet and forums and social media predated its existence, they were just harder to learn about when distribution was more difficult.
And with franchises like Star Trek and Doctor Who also being incredibly popular back in the 60s, a lot of things that people associate with modern fandom were quite visible back then too. The actor who played the 12th Doctor (Peter Capaldi) was into the show enough that his demands to run the fan club and letters to the BBC had some of the production staff joke they wished the Daleks would exterminate him:
The last showrunner before RTD's return (Chris Chibnall) was a vocal member of the fanclub that appeared on TV complaining about the state of the program and its writing:
And fans have written off storylines and elements they dislike since who knows when. If you follow the history of fandom through things like letters and BBS boards and Usenet and whatever else, you'll see many of the same things you see on social media today, whether that's fans rejecting the series 'canon' or timeline or worldbuilding, criticism that things have gone downhill, fanworks and concepts, etc.
The internet merely took this sort of media engagement from something you'd have to specifically seek out, to something that's front and centre on platforms with millions of people.
In the case of Chibnall its quiet obvious why fans are ignoring cannon. He did first. The plot of his run ignored previously established cannon from preceeding season and made large changes to the established lore around the doctors origin, and the entirety of Galafray society said and shown on screen. So fans chose to ignore plots from his time as showrunner. Its like when fans of books ignored unfaithful movie adaptations.
https://en.wikipedia.org/wiki/Fanzine
Many things associated with the internet and forums and social media predated its existence, they were just harder to learn about when distribution was more difficult.
And with franchises like Star Trek and Doctor Who also being incredibly popular back in the 60s, a lot of things that people associate with modern fandom were quite visible back then too. The actor who played the 12th Doctor (Peter Capaldi) was into the show enough that his demands to run the fan club and letters to the BBC had some of the production staff joke they wished the Daleks would exterminate him:
https://www.dailymail.co.uk/news/article-2386587/Young-Peter...
The last showrunner before RTD's return (Chris Chibnall) was a vocal member of the fanclub that appeared on TV complaining about the state of the program and its writing:
https://www.facebook.com/BBCArchive/videos/bbc-archive-dr-wh...
And fans have written off storylines and elements they dislike since who knows when. If you follow the history of fandom through things like letters and BBS boards and Usenet and whatever else, you'll see many of the same things you see on social media today, whether that's fans rejecting the series 'canon' or timeline or worldbuilding, criticism that things have gone downhill, fanworks and concepts, etc.
The internet merely took this sort of media engagement from something you'd have to specifically seek out, to something that's front and centre on platforms with millions of people.