Meat is usually drained of as much blood as possible before it is sliced up for cooking. The juice that oozes out of the meat you buy at the supermarket is not blood, which you can verify by comparing it to your own blood next time you cut yourself: the juice is clear; mammal blood is opaque.

If the only octopus you've ever had is rubbery, you've had the bad stuff. I've had octopus that melted in my mouth. Partly it's the part of the beast you fix (the tentacles will ALWAYS be rubbery; the head meat is much tenderer) and how you fix it (the best octopus I've ever had was in a stew, which was presumably cooked a good, long time). (It was at a Greek restaurant in Chicago, by the way.)

Alex