Yemama, you summed it up quite well. You know, I keep hearing how "healthy" raw beets are, but if you have a sore throat for the entire day, your body is indeed telling you something. I know that's the effect it has on me! But raw beet juice mixed with other juices, some lemon juice, etc. is very, very nice. Also, I've lactofermented raw beets (kvass) and let it age in a cool place for a long time, and golly, is this a lovely drink. The old timers, the traditional people, had no science as we know it, yet look at what they could come up with.
As to the oxalic acid, I read that it was only in the leaves; however, I'm willing to be corrected in this.