From all the vulnerabilities they know, they chose to publish one that's known and only concerns outdated software. Maybe I'm too skeptical but when the NSA starts leaking fixes for zero day exploits, I'll take them more seriously.
Zero-days are far more useful to them as exploitable points of entry as opposed to patches.
Perhaps it's not wise to have the same organization looking after both the defensive aspects of our security, AND also offensive espionage operations.
But I still don't see how that could be a reason to not take this warning seriously.
I think that the cynical view of this would rather be that they consider the potential harm from someone they don't like, making a 1m machines botnet from this, to be greater that the benefit they get from themselves making a 1m machines botnet.
I think the NSA has a real image problem. They released ghidra. They admitted it was a recruitment tool. They now release this warning which basically tells us to update our software. Anyways, if they really want to improve their image, they need to release zero day exploits and prove it's not just an offensive but also a defensive agency.
The release of an exploitable bug might deny them a couple of targets but will protect millions.