If it's the report I think they're referring to, it basically said Aspartame is possibly carcinogenic but safe at normal consumption levels.
It raised a lot of doubt around Aspartame being carcinogenic without going so far as to deem it non carcinogenic, concluding that more studies are needed.
I wouldn't call it overwhelmingly positive for Coke but it's not hurting them.
There have been dozens of studies over multiple decades looking into aspartame and have found it isn't carcinogenic. One Coke-funded study one way or the other doesn't change the massive body of research.
If the truth is that it's a carcinogen, a WHO report saying it's fine in small amounts would be overwhelmingly positive for Coke, I'd say. Just like tobacco companies being behind the studies showing the "healthiness" of vaping as an alternative, even though it might decrease cigarette sales a bit.