These links provide little to no evidence of diet soda being bad. Hopefully you're aware of how population studies have huge, glaring weaknesses from a methodology standpoint.
See e.g. this from the middle one:
The researchers have several theories for the connection. Even though they adjusted for weight at the beginning of the study, they didn't collect weight measurements at the end of the 10 years or throughout the study. Since diet soda has also been linked to weight gain, it's possible that the diet drinkers gained more weight, which increased their heart risks. (Again, just a theory.) And as we reported in our story The Truth About Diet Soda, diet soda drinkers may have worse dietary patterns overall. (Although the researchers conducted dietary surveys to adjust for this, food surveys are notoriously unreliable.) Basically, no one knows for sure what's going on.
Just in the bolded, you see three massive potential confounders. There will be tons of others in self-reported studies like these. I'd wager heavily on the side of "(diet) soda drinkers having worse dietary patterns overall" being a huge culprit myself.
As a huge socialist, I find this ban completely lolz and agree that ending corn/ethanol subsidies would be good. I doubt it'd really do much to affect obesity (would it affect the price of HFCS much/at all?), so not sure what it's doing in this thread though.