Your overall point is not a bad one, but investors don't need "thoroughly backtested trading algorithms" to protect themselves. Frankly, many of the people who use "thoroughly backtested trading algorithms" don't do as well as they supposedly should.
It is, on the other hand, entirely possible for an average investor to learn basic technical analysis concepts and apply them visually to charts. At a minimum, for instance, if you can draw a trend line on a price chart and identify when price breaks important trend lines, you can easily avoid losses from major declines without having to write a single line of code or spend more than 5-10 minutes a day checking on your portfolio.
A decent book in this vein is The Visual Investor[1].
It is, on the other hand, entirely possible for an average investor to learn basic technical analysis concepts and apply them visually to charts. At a minimum, for instance, if you can draw a trend line on a price chart and identify when price breaks important trend lines, you can easily avoid losses from major declines without having to write a single line of code or spend more than 5-10 minutes a day checking on your portfolio.
A decent book in this vein is The Visual Investor[1].
[1] http://www.amazon.com/The-Visual-Investor-Market-Trends/dp/0...