Is a CA 501(c)4 subject to the $800 minimum franchise tax?

Not my usual area of practice but helping out a client who wants to start hosting an annual motorcycle camping rally. For liability and tax purposes they want to set up a nonprofit to operate it and either send proceeds to another charity that helps state agencies maintain public land or hold on to some funds to spend on subsequent events. On the CA SOS site to register as a nonprofit public benefit corporation it says they are liable for the $800 minimum franchise tax. I’ve read CA FTB publication 927, which says all non-exempt corporate entities must pay the $800, but I don’t see a clear answer anywhere that states a 501(c)4 is exempt from it and google is no help on the subject. What do you guys think?

Revenue & Taxation code section 23701 describes organizations that are exempt. If your group fits one of the descriptions, file an application for exemption. It's simple if you already have an IRS determination letter.

What exactly is the exempt purpose of the org?