I would challenge anybody that believes that sodas whether diet or not aren't poison to do a couple things.
1. go to your nearest bottling facility in the early morning. Sit near the truck gate and watch the trucks bringing the ingredients into the facility. You will see so any HAZ-MAT placards it's just not funny ranging from CORROSIVE, FLAMMABLE, & even ,yes, POISON.
2. Do the spoon test. Get a cheap spoon (you dont want to ruin your good ones), pour a glass of soda, and suspends spoon in the soda for several days.
Then decide, do you really want this stuff in your body?