I wouldn't be surprised if the matter protokol somehow needs some google or apple service to function.
homeassistant
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Atleast for android and Bluetooth. Not an absolute matter protocol thing, but probably "normal android allows that only woth google signed app". Some OS access thing and so on. "You don't get to access that Bluetooth matter discovery call mode etc. without official sign off, security hurdur".
Since matter has ways to connected fully without Bluetooth depending on device. Bluetooth is just the easy simple way, instead of having to hunt for pairing QR symbols or number codes. Go to the other device makers app to activate pairing mode or generate one off pairing codes and so on.