Here is an interesting article on understanding the psychology of anti-vaccine beliefs.
The anti-vaccine conspiracy theory holds that vaccines cause a long list of ills. This is taken as a given, an article of faith. Everything else necessarily flows from that premise. If vaccines cause disease, then the pharmaceutical industry must know it. They have done the research. One does not have to be a conspiracy theorist to assume that corporations are hiding inconvenient information to protect their profits.
But then the narrative necessarily gets darker. Not only must pharmaceutical executive know that vaccines are causing harm, it must also be true that the medical profession knows as well. Who do you think is conducting that research? They review the data, and they make recommendations for treatment. The government must be involved as well, because they regulate vaccines. The Center for Disease Control (CDC) reviews the published science and makes recommendations for the vaccine schedule. So they must be in on it.