Instead of just saying they won't do it for free accounts, they could charge a fee for the service.
Which is worse publicity:
A) if you use this security feature, and something goes wrong on your side, you will lose your account forever
B) if you use this security feature, and something goes wrong on your side, helping you get your account back will require a lot of work and due-diligence which we can't afford to do for free
It's not SO different from:
A) if your device fails outside the warranty, it cannot be repaired
vs B) if your device fails outside the warranty, it will be expensive to repair
I think it's not so clear. If someone tells me "I can't authenticate, and so I'm locked out of my account", that sounds like his fault. If someone tells me "I can't authenticate, and they'll let me into my account, but only if I pay them money", then that sounds like their fault. I do carefully say sounds—I recognise the underlying tech is the same in both cases; but the nature of publicity is to attach much more about appearance than to technical facts.
Otherwise, with no path forward, this is just user hostile.