This does not blanket apply to all Xiaomi devices. There are official builds of CM available for the Mi3, Mi4, Redmi Note 3, and a fully open source unofficial

This does not blanket apply to all Xiaomi devices. There are official builds of CM available for the Mi3, Mi4, Redmi Note 3, and a fully open source unofficial build for the Mi4C and Mi4S. Unlocking their bootloader can be done officially through a request, or unofficially. Changing the recovery by replacing a single file in the EDL and retaining bootloader lock is also possible.