XMR Dev team rose to the challenge of forced evolution in the time available.
They have crafted a polymorphic bitmonerod+client that adds checkpoints at will and with no dev team intervention needed. Its a decentralized self-maintainable solution that scales as needed. Even if you DDoS github, checkpoints can still be deployed.
That's not the case according to the post that you linked
We will be distributing updated checkpoint files that will continue to protect the blockchain without the need for a full update of the daemon.
If the clients had ability to add checkpoints at will, I believe that would
lead to forking, unless the reorg procedure is fundamentally different from
bitcoin-based coins.