"Snake oil" is one of the first terms that popped into my head, too.
While I've only been caring for a pool for about 2 years, I've spent my career working in water quality, wastewater treatment, and water chemistry for the second largest environmental agency in the world. I've seen slick salesman dupe seasoned environmental professionals time and time again that they had some proprietary solution that would solve all the world's water problems. I too foolishly let someone convince me early on that swimming pools somehow defied the laws of the natural world and that they were some unfathomable "chemical soups" that no one completely understood.
Once I found this site and started approaching things scientifically, logically, and acknowledging what I already knew about water quality, I realized that there was no rocket science here - it's just basic water chemistry - pH, alkalinity, hardness, and the use of oxidizers to consume organic matter and destroy potential pathogens.
As another respondent above has said, I wouldn't hesitate for one second to drink the water in my pool - I know exactly what its chemical composition is, and I know what the CL2 levels are - and they're significantly higher than the drinking water that's delivered to my by a municipality.
As a whole, people don't understand chemistry, and that makes them vulnerable to believe all kinds of sales pitches for miracle cures. In the end, basic water chemistry has not changed since the first instant in the universe that two hydrogen atoms combined with an oxygen atom. Once we realize that, everything else just falls into place.