Really it comes down to the media not being good at presenting science topics, which is pretty typical unfortunately.
In the end, I consider the WHO as having lost all credibility - it doesn't matter why articles based on WHO statements cannot be trusted (e.g. whether the WHO statements are factually wrong, or intentionally misleading, or being communicated in ways that media are likely to misinterpret without quickly following up when this happens), the result is that any article claiming "WHO says X" is best dismissed as likely misinformation.
I mean, sure, you can distrust WHO if you want because of this, but seems kind of a silly reason.
But the whole purpose of a press release is to communicate accurately with the press. The WHO, being a global organization, is also very much supposed to work with the press globally.
Not to mention, the aspartame story was not coming out of some small paper from Trinidad, it was coming out of major publications in the USA. If the WHO can't even manage to communicate properly to them in its press releases, why bother putting out press releases at all?
There are plenty of Americans who were properly able to parse the WHO press release. Our corporate media doesn't hire them because they choose more eyeballs with strong emotional reactions (to sell to advertisers) over a well informed audience.
It's naive to think WHO could have crafted the release in a way that US major networks would have reported on it responsibly.
1. What is success in public health communication for the WHO? An organisation that operates globally, in many languages, at all levels of economic development, and no mechanism of generating its own revenue?
2. If you believe the WHO to have lost all credibility which group of public health experts could you consider credible?
Journalism's job is to convey complex nuanced topics to the populace at large. If journalists aren't doing that, they're failing to do their job. I appreciate at this point that may be a quaint and archaic expectation though.