Do you have that one friend, or that relative that does nothing but create chaos in your life? If you do then you know how disruptive and hurtful they can be. It puts everyone involved in a bad position. Do you choose sides or remain neutral? To the “offended ” person there may not feel like neutrality is possible. If you associate with the one with a grudge you have actually chosen a side.
Now the one who has been shunned by the toxic person is utterly alone because others choose not to choose which in reality is a choice.