And of course there’s the politicized paranoia of contaminating the public water supply, and who should get to decide such things, and why they might choose to do it.
But, those stories usually focus on intrigue, and don’t explain much about the chemistry of the element flourine, ionic compounds, or much of anything else, and dissolve into hand-wavey boogie men.
You basically get two incomplete pictures of the same story. What both sides leave out is that flouride has medical utility, but while toxicity is a potential risk, it’s not some mysterious subversive threat, and the benefits weigh favorably against the side effects.
Also, no one ever tells you that a little bit won’t hurt. Opponents offer hysterics of zero tolerance for poisonous toxic waste and brain damage. See also, Dr. Strangelove, and the idea of precious bodily fluids.
Meanwhile, advocates never tell you that you might be okay with flouride toothpaste just once a week, and no flouride at all the rest of the week, brushing with just pure, ordinary water (Mandrake). Instead, advocates advise twice a day, ...no more, but certainly no less.
And proponents of public flouridated water usually sidestep the premise of prescriptive public health as offering a leg up to people who might not have disposable income for toothpaste. Charity chafes all sides. Some might be too proud to accept the premise of assistance. Others bristling at the undertones of that idea amounting to other people’s needs conflicting with the autonomy of those with the capacity for choice between such options.
If you don't need fluoride, even water works well:
https://www.ncbi.nlm.nih.gov/pubmed/27513809
"The cumulative evidence for this systematic review demonstrates that there is moderate certainty that toothbrushing with a dentifrice does not provide an added effect for the mechanical removal of dental plaque."