The big difference here is that nobody is being forced to use dental floss against their will.  That's very different from water fluoridation, which gives everyone a dose of medicine because it's good for their teeth  --  whether they have teeth or not!   

If every morning, every citizen of Port Angeles woke up with floss sawing away between their teeth, and if it cost every household thousands of dollars out of their own pockets to make the floss-attack stop...  then this letter might be amusing. 

The best-proven effectiveness of fluoride is in its topical application  --  including the simple use of fluoridated toothpaste.  

For those who are determined to have systemic ingestion of fluoride compounds, it is cheap and easy to hand out fluoride tablets  --  in the schools, for example, with parental permission.  And healthier, too  --  those tablets are pharmaceutical-grade fluoride, free of the toxic outriders of the industrial compounds used in municipal water fluoridation.