Why do commercial toothpastes sold in US have toxic chemicals and poisons in them?

Fluoride is already classified as poison scientifically and that's undisputed. Thousands of google searches confirm this. Its an ingredient used in rat poison, sarin (a weapon of mass destruction), and it is collected from pollution and nuclear waste sources. Yes there is some dental evidence that it is anti-cavity in nature, but our tap water is already very heavily fluoridated which eliminates the need of fluoridating toothpaste. Excessive fluoride consumption can lead to various physical ailments and that is undisputed too. Secondly toothpastes contain an ingredient known as sodium lauryl sulfate, which is source of canker sores and gum irritations. Thousands of google searches also point to how rough SLS is to the body. It is a very bad irritant and it is used in coolant of car engines. Companies like colgate and crest pride themselves for being leader in heavily fluoridated and SLS products. I personally use natural toothpaste that is free of fluoride and free of sodium lauryl sulfate, and they are more than double the price of commercial toothpaste which again confirms that the better the product the more expensive. Since 2007, I have been using fluoride free and SLS free toothpastes and I never had any cavities and every 6 months I get dental checkups and x-rays always show zero cavities and clean teeth. So then why are commercial brands of toothpastes like colgate, crest, arm and hammer, aquafresh etc etc still producing toothpastes full of fluoride and sodium lauryl sulfate? Also not everyone can afford natural toothpastes which cost more than $7 a tube in such tight economy. It is seen as luxury instead of necessity.