Quark's

There are probably a few things going on.

• First the algorithm rewards videos that drive interaction. That can be angry comments, up or down votes, subscriptions, whatever.

• The algorithm will drive you towards more content of the kind that you interact with. If you interact with conservative leaning videos that will drive what it shows you in the future.

• A lot of scifi (although forward looking) is driven by nostalgia. People remember reading heinlein, azimov, etc in their childhoods. Nostalgia often comes along with a strong dose of traditionalism. People want to hold on to the old versions of things. Old stories, old ways of doing things.

• The role of reviewer can be somewhat inherently regressive. Reviewers can respond badly to change, differences from what came before. They can hold back innovation when they don't understand how to conceptualize something new. They can be incentivized to adopt the consensus opinion of other reviewers.

• If you love something you're less like to have a successful channel. People love to watch cinema sins, nostalgia critic, etc. People giving bad faith angry yelling into a mic reviews that become a series of low effort jokes. If you love something there's often less to say, fewer jokes to make, and less to engage with. Star trek is progressive, so if you're someone who loves it, you may be less likely to make a forceful critque of the kind that's been in vogue on youtube.

• "geekdom" in general had often had an exclusionary bent. See the sad puppies, or gamergate. At one point geek culture was a safe haven for outsiders who felt that the world didn't or couldn't understand their interest. It was a place to meet other smart people, and talk about the stuff you care about that not everyone will get. Unfortunately that also comes with a lot of broken people who see a place with a lot of smart people as a place to be "superior," see discussion forums as a place to flex their might knowledge of canon and browbeat newcomers to franchises, or see geekdom as a place that they dominate from which other must be kept out-- hence the "you're not a real nerd" stereotype. That seems to tie in with a conservative mindset about social issues.