That's certainly true; NSA is chartered to exploit vulnerabilities and certainly hoards them. But that doesn't address the question of whether you should trust NSA "on crypto". Here, they're the ones disclosing the crypto flaw; there's no need to "trust" them, because they're clearly right (Saleem Rashid worked out a POC for this on Slack in something like 45 minutes today).
Should you trust them about Dual_EC? Obviously not: the sketchiness of Dual_EC has been clear since its publication (the only reason people doubted it was a backdoor was that it was too obviously a backdoor; I gave them way too much credit here).
Should you trust them about the NIST P-curves? That depends on who you ask, but the NOBUS analysis is very helpful here: you have to come up with a hypothetical attack that NSA can exploit but that nobody else can discover, otherwise NSA is making China and Russia's job easier for them. Whatever else you think about NSA, the idea that they're sanguine about China is an extraordinary claim.
Should you trust them about Dual_EC? Obviously not: the sketchiness of Dual_EC has been clear since its publication (the only reason people doubted it was a backdoor was that it was too obviously a backdoor; I gave them way too much credit here).
Should you trust them about the NIST P-curves? That depends on who you ask, but the NOBUS analysis is very helpful here: you have to come up with a hypothetical attack that NSA can exploit but that nobody else can discover, otherwise NSA is making China and Russia's job easier for them. Whatever else you think about NSA, the idea that they're sanguine about China is an extraordinary claim.