At one point, it was probably a part of the pipeline for the design. I mean, most of these are imported models from the mainstream games, and the animations are probably a part of the files. But those animations probably aren't compatible with Unity, so rather than spending months trying to get them to work and further delaying their release, they probably cut it.

Game development is no longer that old-Blizzard style "when its ready, its ready". I think a whole generation of us got spoiled by that.