Will here's the thing. How can you trust anyone in the vast internet? There are people with good knowledge and they might share it for free. But what if they have a hidden agenda behind that? For example, imagine a guy spreading good knowledge that they have acquired in the life. Most people who will try it and get success will surely trust that person. And if that person have the hidden agenda, you will then use his other knowledge to manipulate people. When you put one lies between 10 truths, that lie becomes a truth. The same goes for people who are manipulating using their knowledge.
They will share more than one good knowledge and then mix that up with one bad knowledge that with lead to a doom. And you won't be able to blame that person right? He has done all this for you and that was just a one mistake. We are all human and we all make mistakes. So that one intentional mistake gets buried under those successes. And that's how those people manipulate others.

It is hard to find the right material or information on the internet nowadays. Even if you find a legit one, you never know what is coming in the future.