I have some sympathy for this. With the disasters of the WD 'Green' series and the recent revelations on how used disks were being sold for new. Synology doesn't want to be lumped with other companies problems. They really have to sell it by minimising the price differential and reducing the lead time.
This is the same old tired argument Apple made about iPhone screens - complain about inferior aftermarket parts while doing everything in their power to not make the original parts available anywhere but AASPs. Except here we have the literal same parts with only a difference in the firmware vendor string.