It would be great to have MOOCs about SecureDrop. The edX platform is Free Software, can be self hosted and a company provides managed instances for a fee. I’ve had good experience managing and training non technical people to use a small instance, as a trainee and as a course producer, for a political non-party running for the French election last year. The MOOC is still up at https://mavoix.opencraft.hosting/.
Full disclosure: OpenCraft CEO is a friend.