Teaching bitcoin to others is a good idea but to do that you need to have enough knowledge, experience or even deep expertise to be able to teach others and take their money. You can't take advantage of people's ignorance and give them knowledge about bitcoin when you yourself don't have too much knowledge about bitcoin. Not to mention, knowledge about bitcoin is not too difficult to find on the internet and everything is free. So if you want to open a center or a class to teach about bitcoin, there is nothing wrong but you need to provide them with knowledge commensurate with the amount of money they pay you. Education may sound simple but it is no simpler than business related to bitcoin.
I think there is no problem if someone who is experienced and has a lot of knowledge of Bitcoin can make people aware of Bitcoin for a small fee and it will be great. There is no doubt that everything is there on the internet, but it takes a lot of time to search and find the right information, on the contrary if someone can provide good knowledge for a small fee then I think it would not be bad.
Other than that, I agree with you. A person who has no knowledge himself can't teach others, whatever knowledge it is, they need to learn it themselves first because only a knowledgeable person can teach others. Without acquiring knowledge, if a person makes such a mistake, he can make people lose thousands if not millions of dollars. Therefore, it is important that you yourself are fully trained and have learned everything before teaching others.