Chuck, based on your responses, you do not seem to be making a distinction between an initial release of software as a "centralized authority" and a checkpoint that was later announced for users of an existing cryptocurrency.
This discussion about the genesis block being a "checkpoint" is pure nonsense because it is as much a part of the definition of bitcoin as the protocol, the 21 million coins, the digital signature algorithm, etc, etc.
If you say things like "how do you know
cats aren't dogs a genesis block is The Genesis Block," you could also say "how do you
know that bitcoin has a 21 million coin limit? How do you
know that bitcoin uses ECDSA? How do you
know that you know?
If you deny objective reality and if you refuse to accept that words have specific meanings, then debates devolves into mush like this one has.