The data used in this study came from self-report surveys and questionnaires that mainly seemed to ask when and if they were diagnosed with type-2 diabetes. The results were adjusted for quite a few factors like obesity, socioeconomic status, and daily sugar intake, but I didn't see anything about overall dietary patterns or physical activity levels. I did see the phrase "physical activity" in the footnote of one of the tables, but no further context. The top end group was those who had more than one drink per day, which implies that two per day and a 12-pack a day were treated as functionally the same. And they admit they weren't able to differentiate between types of artificial sweeteners.
Similar studies referenced in this one point out consistency in observations among the sugar-sweetened beverage group, but the results from artificial sweetener groups have been all over the place.
I'd take this with a huge grain of salt. Or artificial saltener.