Aspartame is listed as possibly carcinogenic now after having "0 problems" for decades and having that same claim of being some of the most tested food additives on the planet. Most artificial sweeteners are also still linked to problems with insulin response, weight gain, and diabetes which are the things we were trying to prevent by drinking them in the first place. Do some more research and you'll find things like links to cognitive decline, clotting with things like xylitol, depression, gut microbiome problems / even possibly intestinal wall integrity issues (sucralose-6-acetate).
The science was settled (and probably mostly funded by the companies that sold the products) right up until it wasn't. Now there seems to be huge concerns. I wouldn't be surprised if some of these substances are banned within our lifetime.
That said, the topic here was on cancer, and even the WHO announcement about aspartame being possibly carcinogenic clarifies it's not for normal ranges of consumption. I think you're trying to make a boogie man out of scientists and researchers by mischaracterizing the complex work they do. If you feel that things have suddenly reversed course it's because you haven't been following the research.
The actual question is: would drinking that stuff with sugar have caused more damage to health? And the answer will likely be yes. Because we _know_ just how bad sugar is for you. Particularly diabetes, microbiome changes, addictive behavior, obesity of course, cardiovascular issues...
If you'd look at sugar in isolation, as a new substance that stuff would never be allowed in any country at all.