Hello, guys. So, I'm back today to give my answer to yesterday's question. I'm not forcing you to accept my answer, 'cause it's completely from MY point of view.
As many of you said, you would still consider her/him your friend, but not "best" friend anymore.

First, I would like to let you know somethings about me. As one of you said, she'd been in a situation like this recently and she feels kinda betrayed for that. I don't know exactly what had happened to her friend, so I won't judge this.
But personally, I've been in a situation where I really felt betrayed, not because she left me, but because she betrayed our friendship and I was really misrable at that time, but after some time that I met her, we greeted each other normally but I never address her as my friend and if someone asks me if I know her or not, I would just say that I know her and she was a classmate of mine.

About the question, it had happened for a lot of us in real life and like many of you, I say that she's still my friend and in my own life, I've had many close and not-so-close friends that after we were separated, they haven't called me unless I call them, but they're still my friends.

Now, I want to tell you the relation between EXO's situation and the question I asked from my point of view and I'd like you to know that I didn't have any girl cousins my age and I was grown up with my boy cousins, so I'm kinda familiar with their way of thinking and also heard things about exo's situation that can explain my thoughts.
So, as all of you may know, the original EXO had 12 members that you could always see in programs that how they relationship was and they were really like brothers to each other. So, their relationship was something more than just simple friendship.
Then if you remember, in the example I wrote that your friend leaves because of some personal reasons that may be unknown to you, but in EXO's situation you all can see that why a lot of artists and not just Kris and Luhan left SM, they've all been under some pressure that you can not imagine, 'cause you've never been in their place. So, they left with a well-known reason, so I don't think that the other members felt betrayed, I think they just felt kinda disapointed.
About boy's relationships, you may know that in situations like this, unlike girls, they confront it more logical and whatever that happens between them, their relation almost stays the same as before.
So for exo, I'm almost sure that their relation is still the same in their hearts, although they can't or won't show it.
I remember that a few weeks ago, I read this new somewhere that said Kris had given a ring to Chanyeol which he put it on even after Kris left exo, but after some time, SM forced him not to put it on anymore and another news that said he posted a message on instagram and after SM saw it, told him to delete it.
And also, if they're not the same as before, why would Lay still fallow Luhan on instagram and also Luhan fallow Sehun? Why would they meet each other if they're not the same as before?
Why would people/fans call them betrayer while they don't think the same way?

and also, Tao is not even gone that some of you said 9.

So, this was my answer and about the poll, I would choose 12, 'cause we all knew and still know exo as 12.

Thank you so so much for reading this and also giving your answers to my question.
( I repeat that this was from MY point of view and nobody foreces you to change your way of thinking)