There is no reason for any manufacturer to make it nearly impossible to perform a repair on their airplane. Who would it benefit?
I wouldn't argue they're trying to make it
impossible to repair the airplane. Rather, given the way the LSA rules are set up, it presents a very tempting opportunity to run things such that repairing the airplane requires paying them through the nose.
This is not an unusual thing at all, in the broader sense. Look at the (anecdotal?) attempts by car manufacturers to try and deny warranty service if work was performed somewhere other than the dealership, or if any scheduled maintenance was not performed. Look at attempts by electronics manufacturers to use proprietary hardware and encrypted software (and attempts to use DMCA as legal deterrent) to prevent modification or repair of items outside authorized service centers. These are all attempts to limit the supply of repairs/parts and thus increase prices.
I think the FAA naively set up repairs as requiring manufacturer authorization thinking that manufacturers could release maintenance and repair manuals without having to go through the approval process, and so they could permit a broader scope of repairs. In reality (because nobody reacts to FAA regulations the way the FAA expects and intends them to), some manufacturers have chosen to go the opposite way and withhold repair data and parts as much as possible, such that owners have to pay significant sums of money for replacement parts, repair drawings, or repair work done by the manufacturer.
The FAA really needs a "red team" when they sit down and do their regulation-writing...
