Social skills are very important because you're not a one-man-show.
You have to work on a team and get along with the group. Everybody is there to help the client finish his/her movie. Every project will go through crunch time, where everybody has a lot do and people are stressed out.
It is during those moments where you have to be able to stay calm and get your work done, regardless of what is happening around you. You will depend on other people's help and vice-versa. Again, it's all a team effort.
There is no room for an ego, jealous behavior, or other attitudes and your animation skills alone won't save you. You also need to be comfortable receiving feedback as well as giving feedback, especially once you become a lead animator, supervising animator or beyond that. Sooner or later you will have to deal with production people around you-- producers, directors or whoever is involved with the project you're working on. Having no social skills is not going to make those moments very enjoyable.
I haven't been involved with interviews but I would definitely look for appropriate social behavior in an interview. People will judge you and if you come across as arrogant, awkward or selfish, etc., then your chances of getting hired will diminish.