Assuming what Ledger says is true and they use French pick & place soldering service, they only receive bare PCBs from China.
How would 'the Chinese' install a backdoor on a bare PCB? You know, this kind of stuff
Why would I trust anything that people from ledger are saying, when it's proven they are either liars or they don't know facts about manufacturing?
Backdoors are most likely hidden on microchips, not in PCB's, and it could be similar like with smartphones with encryption that can be decrypted by governments.
I don't understand they would invested bunch of money in making videos, music videos, promotional campaigns with celebrities, etc. but they keep hiding origin of their components.
Ledger is Made in China and Assembled in France, nothing wrong with that, just be transparent about it.
I don't trust that myself; I'm just saying, if we assume it's assembled in France, and they only get bare PCBs from China, the devices can't have 'Chinese backdoors' on them. Except if they buy backdoored components of course, but as you said, everyone gets their components from China.