Actually I think you have it backwards. The notion that traders consistently beat the market is hurting a lot of people. There are extremely few traders who beat the market year over year. It becomes vanishingly fewer every year you add. Which is what you would expect for a system where luck plays a big role and nobody can actually predict the market.

Tldr; way too many people believe that a lot of people can beat the market and that is what actually hurts the most investors.

edit: spelling