Actually, that FAQ entry itself already counters your argument:
"Treat it like you would payment - you wouldn’t write a whole payment gateway like PayPal - but instead use a 3rd party."
Where's the difference?
By the way, you can always allow users to connect several OpenIDs to a single account – this way, worried users can provide redundancy themselves, if desired.
By the way, you can always allow users to connect several OpenIDs to a single account – this way, worried users can provide redundancy themselves, if desired.