I think you are trying to mix morality with the business of making money, never a good plan. Most people who are trying to sell something think their target audience is either stupid or ignorant, check out advertising for proof of that, and generally don't care about the ethics. That's why I love Americans, they form one of my "alternative" pension plans, if you say it loud enough, and often enough, and throw in some "proof" they'll not only believe you they'll actually send you money...more than once!
Short answer, no it isn't wrong to make money from people who believe things you think are stupid, there are so many dumb beliefs out there it's literally inevitable you will make money from stupidity.