If it had been for a longer period of time, then I would agree with you. As it was only six months or so, and at the most had lost 20% of their weight, they were far from starving unless already emaciated when he started the experiment. I would assume he had used snakes that were a good healthy weight.
I like snakes too, I wouldn't have so many if I didn't. As far as the blending part, sure it's kind of sick, and not something I would want to do myself, but the animal was euthanized prior to it. Had the animal been thrown in the blender alive then you can bet I'd be outraged. I would assume ball pythons were included in the study because they're the cheapest and most abundant species of python in the US.
I don't see how being euthanized or dying of natural causes has anything to do with being put in a blender. There are people out there who do much worse to ball pythons. Remember those kids who nailed a living ball python to a telephone pole? Or how about that football team who bought one to kill on the field for good luck before a game? Or all the negligent owners out there who keep them in horrible conditions?
I really don't get how you think it's ok to throw one species of snake in a blender but not another? As far as the morphs go, they're still ball pythons. The only thing I could see it changing would be if a certain morph didn't handle a lack of food as well due to a weaker physiology.