This just came to my mind so I felt like it would be ok to just talk about this.
Imagine that you are a member Z of an idol group. There is member A which you easily like and your personalities fit well. There are also members B, C, D, E, F all of them different. Member D somehow can't have any proper conversation with you. You're clicking well with others. Through time you became neutral with D, luckily both of you also have some bigger or smaller CF's.
Then from D's perspective other members like to be around you, they seem to be more talkative and joking with you. So sometimes D is feeling outcasted or not that "liked by others", because D spend most time alone or with member E, and just sometimes member C joins them.
No bullying within group. Just some people growing apart through time or just not getting closer.
What's your take on this? Because in my opinion in this kind of situation if there would be one argument or some quarell it might get bad to the point "I don't feel like a member of a group".
But is it really Z's fault? Your fault?
Nope it ain't. It isn't anyones fault, but if someone should be blamed then... It rather should be D.