It is declared a poison but we still use it everyday and drink it

Live healthy and long

From Dr. Mercola archives

It is considered a poison, it has adverse effects on IQ,  causes arthritis, cancer, bone damage,  dementia, muscle disorders,;  other countries have stopped its use but we use it still in our health care products, and even for drinking water in the US.

What is this element?   Flouride

It is still in my toothpaste.  Why is FDA still allowing its use?  Why has FDA not stopped its use?