>> Probably fud, but it slowed down adoption of eliptic curves.
Not FUD at all. NIST revoked their recommendation to use those curves because of it. The facts are that a "backdoor" exists whether anyone knows what it is or not, and NSA could not explain how those particular numbers were chosen so out of caution we must assume they know the backdoor and not use those curves.
I believe you are mixing up NIST ECC curves with Dual_EC_DRBG[1] which is a random number generator based on elliptic curves which is widely considered to be backdoored and they revoked its recommendation (there are much better ways to construct an RNG so it was stupid to use in practice for reasons other than backdoor too.)
The P-series curves are still a NIST recommendation and widely deployed in TLS. The B-series fell out of fashion due to practical reasons.
Not FUD at all. NIST revoked their recommendation to use those curves because of it. The facts are that a "backdoor" exists whether anyone knows what it is or not, and NSA could not explain how those particular numbers were chosen so out of caution we must assume they know the backdoor and not use those curves.