I haven't met an Alexandrine but the ringnecks in general do have a reputation for being less "tame".
My opinion - based on a very very short time of having a ringneck, meeting some Indian ringnecks, and volunteering with other types of birds, is that they are more independent - my bird is happy if I'm in the room but he also is happy to play by himself. From talking to other ringneck owners I've met this doesn't seem too unusual.
Maybe this quality is why they aren't as motivated to befriend people as some other parrots? I don't know.
Maybe some of it is their body language? My ringneck shows very subtle signs when he starts to be uncomfortable and it can be really easy for me to not notice (especially when I first had him home). Then he reacts in a more obvious way like stepping away from me the next 30 times because I was not reading him correctly when he just used his eyes or a tiny twitch of his wings. He can definitely read me better than I can read him!
I am by NO means an expert on ringnecks - I'm totally guessing here. My ringneck is not scared of me, but he will definitely run away if I don't pay attention to what he's telling me, for example. Where my son's cockatiel will just keep trying then will bite to get his message across. It's a difference in communicating to us, in my opinion.
I've come to really love all the ringnecks - I think Alexandrines are absolutely beautiful and I hope to meet one some day!