The stigma arises from industry alone. This industry was not built on honesty. Scams in the industry are in pretty much any sector. Education rooms, chat rooms, prop firms, banks, wire houses, government.
Someone is always trying to take advantage of others. Those firms (prop, chat, etc.) that are legitimate unfortunately get painted with the same brush as the higher percentage of those that aren't, but that's the industry they chose to do business in so they have to live with it.
Firms that treat clients right eventually get above the fray. So the answer is "No", not all are bad, but it will take some time to find the right ones to fit your needs.