Most people buying stocks don't understand the company as well as someone who works in the sector.
Most casual art appreciators don't know how to tell if a painting they're buying is a forgery.
Most people buying a house don't know how to assess the foundation, and even if they get a professional assessment, they don't have the same knowledge of the housing market as professionals. Maybe that neighbourhood is slated for rezoning in 5 years that would devalue the property.
Heck, even people buying gold/diamonds get ripped off on fakes/synthetics.
Outside of investments, most people here have probably bought a car. Do people who buy a car deserve to get ripped off if they don't understand how every component works well enough to inspect it themselves?