Board Thread:General Discussion/@comment-6901880-20130304064503/@comment-5398287-20140104160509

Erm...Quincies ARE a race unto themselves. They have bloodlines that grant them powers, it's not something that a regular old Human can become through training, unlike Souls and Shinigami.

And Shinigami have "Soul" as their race because Shinigami is a profession, which is why Ichigo can be identified as a true one, though he's not dead.