People who are just now discovering Kirk/Spock, or who didn’t know Kirk/Spock was already a thing.
I don’t think you understand.
This is not a new phenomenon.
The Kirk/Spock fandom COINED THE TERM “slash” in the first place. IN THE 70S.
They wrote fanfics and sent them into fan ‘zines before the internet existed. Nobody knows slash like the Kirk/Spock fans know slash.
Kirk/Spock is the FLAGSHIP of SLASH.