You say these people are folk that you have been a subscriber to, but they are still strangers, aren't they? They are not people you know in real life?
Personally, I wouldn't accept someone as a Facebook friend that I don't know in real life - in fact, I don't even accept all people that I know in real life. I don't want random Facebook friends, I just want to keep in touch with real friends and close relatives on Facebook - people I know and like, but don't get to see face to face all that often (e.g. my brothers, nieces and nephews).
My aim is to have few Facebook friends, not heaps. I cannot see the point in "keeping up with" people I don't actually know and care about. Mere acquaintances are not people that I want to have cluttering up my wall on Facebook.
So, maybe the people you request friendship with on Facebook are curmudgeonly people like me, who cannot see the point unless they know you personally. And that means it is nothing personal about you - they might just be Aspies who don't like Facebook all that much, or only like it for very specific things.