If you have time to analyze, understand or make an investment with knowledge why not take a risk of it than taking courses which the same you can get in the internet, well possible we have different learning phases but think twice if its realty worth it?
On the other hand, I don't know the reason why it is so easy for them to put their trust, but one thing I believe here is that the urge to get rich quickly and instantly is in their minds.
Well because that's the reality in trading. You can truly make money like your annual salary for a day instantly. BUT the questions is, do you have the skill to make it consistently and to keep the money you are making or maybe you are just gambling. Because that's the fantasy most traders are submitting to. They thought success would be earning the million but the truth is how to they are able to keep that million and make another million the next month.
Success in trading is possible but it is not guaranteed. Only those who are willing to pay the price early on can catch up with the rewards of it. It's no get rich quick. It takes years to make money in a day.