I am honestly very triggered by any tone of elitism in the sphere of intellectual or professional pursuits. It's not just in tech - just try googling 'DIY HVAC Repair'. Now, I don't advocate partaking in activities which are legitimately dangerous without training and certification (e.g. charging an HVAC system with freon or operating a crane), but when all you are trying to do is replace a contactor in your HVAC system and you get a wall of "DIY is not allowed here" when asking basic questions, it really puts some hate into your soul. Cryptographers give me the exact same sensation with their 'no DIY' rhetoric.

At the end of the day for me, it mostly boils down to some ulterior agenda which seeks to keep competition or perceived threats to the incumbents' control at bay.

Does the NSA have a vested interest in most technology workers being able to competently roll their own encryption schemes? From my very jaded political perspective, I would say absolutely not. It arguably makes their mission exponentially harder if they have to deal with novel approaches to securing communications. They would probably prefer everyone just use ECC with their hand-selected curve parameters.