Technology

Because AES is NOT vulnerable to quantum computing.

I have not been following the quantum computing attacks on cryptography, so I'm not current here at all.

I can believe that current AES in general use cannot be broken by existing quantum computers.

But if what you're saying is that AES cannot be broken by quantum computing at all, that doesn't seem to be what various pages out there say.

https://crypto.stackexchange.com/questions/6712/is-aes-256-a-post-quantum-secure-cipher-or-not

Is AES-256 a post-quantum secure cipher or not?

The best known theoretical attack is Grover's quantum search algorithm. As you pointed out, this allows us to search an unsorted database of n entries in n−−√ operations. As such, AES-256 is secure for a medium-term against a quantum attack, however, AES-128 can be broken, and AES-192 isn't looking that good.

With the advances in computational power (doubling every 18 months), and the development of quantum computers, no set keysize is safe indefinitely. The use of Grover is just one of the gigantic leaps.

I would still class AES as quantum resistant, so long as the best-known attack is still some form of an exhaustive search of the keyspace.