While I agree that Lufthansa failed to accommodate you in a way that satisfied your disability, I also want to point out that upgrading a customer to business class is not required. If you feel a business class seat would accommodate you in a way that makes your disability easier to deal with, then you would need to purchase that business class seat. Simply because there are empty seats in the business class cabin does not mean that airlines are obligated to upgrade any person with a disability, or any person for that matter.
Again, I agree that LH did not handle your seating correctly in your purchased cabin, which was coach.
It's unfortunate that many people seem to think they deserve "special accommodations" by receiving upgrades for free. It makes all of us with disabilities look bad.
Sorry to sound so harsh, you just hit on a very touchy subject for me.