"What the group considers to be dickish WILL change. Even if a group agrees now, all groups change over time (even if the members stay the same their environment definitely doesn’t)."
It's interesting how we adapt our sense of normal based on consensus even within the smallest of groups. If you have a team of 5, and 2 are replaced, the dynamic for the remaining 3 changes based not only on how they individually interact with the new people but also with how the incumbents as a whole interact with the new people.
If A,B,C interact with D,E. Then A's relationship with D also depends on the interactions between BD, BE, CD, and CE