The same ‘reasoning’ implies chlorination of water doesn’t improve health, and while one is at it, they might as well stop using bleach, and then get rid of soap in general.
Statistically, folks are better off with bacteria being killed off in their drinking water supplies, so it isn’t an unreasonable policy to implement in public potable water supplies.
I’m not surprised that a generation that has grown up with these amenities, might also be lazy enough not to brush their teeth, and statistically end up with as many oral hygiene problems as previous generations.
Chlorine is added to treat the water. Fluoride is added to treat the person drinking that water. Since fluoride is neither a nutrient nor required for healthy teeth, it’s defined as a drug because it’s meant to make a bodily part change.
Drugs should never be administered in the water supply and dosed based on thirst not need, health, weight, etc.