Well… at first the previous replies were about AES, which has nothing to do with the part about elliptical curves you quote.
But have a detailed look at their explanation:
NSA has decided that it may be more cost effective for some NSS to continue to use RSA and Diffie-Hellman […]
NSA does not want to force NSS operators to pay for two cryptographic upgrades: first from RSA/Diffie-Hellman to ECC and then from ECC to quantum resistant cryptography.
So what they basically saying is: Don’t bother about upgrading your system to elliptical curves, rather wait until you can upgrade to quantum-resitant encryption. Otherwise you have two work two times.
This is no argument against ECC! They only argue that large DH keys are not less secure than ECDH. And that’s correct. The one argument why you might want to upgrade to ECDHE is speed.
And they also say you can use elliptical curves:
NSA supports the use of NIST P-384 in NSS.