Take a look again at the trail pix. He was most definitely NOT on the bit, nor was he 'elevated'. Again, the double is not used that way. You can't lift a horse with the double and you should NOT.
Schooling in the double is tried and true. Look at the millions of pictures available online. There are so many horses schooled in the double. How on earth woiuld you show in the double if you never schooled in it? It's not an instrument of torture-- it's subtle when used correctly, which I hope I am doing. I trust my instructor to tell me when I am screwing this up. My instructor is VERY competent and HER instructor is as well. I take lessons with both of them.
The instructor's instructor trained with some of the biggest most classical names out there. SHE is the one who told me to put him in the double and ride him in it every day, and only ride him in the snaffle to test him.
Kneejerk reactions such as yours are not really very informed or friendly.