Actually, that's pretty misleading. It wasn't just one paper. Plenty of studies showed negative side effects. The methods of those studies were disputed, but it's not like there was some unbiased blessed by the angels end-all study that concluded there was absolutely 100% no link between Aspartame and cancer. There may have been possible other contributing factors to the cancer discovered in the subjects of the Aspartame to cancer (or whichever health risk) studies, but that doesn't inherently preclude Aspartame itself from being a contributing factor. It's like saying smoking doesn't cause cancer because some subjects in the study have grandparents that had cancer or lived near a power plant or a paper mill or ate trans fats or visited southern Utah in the 1950's or own a microwave. It obfuscates the direct link, but it doesn't eliminate it.
To be clear, no credible study (not funded by a beverage or chemical company) has ever been published that said Aspartame is completely free of health risks and/or carcinogens (especially for the thousands of Americans unable to properly process phenylalanine).
There's no such thing as 100% safe for humans.
That is an interesting fact. It still tastes like ****.