The quick answer is ABSOLUTELY NOT! There is no rule or regulation, in Florida, that requires a Florida Licensed Home Inspector belong to any organization. By doing the 120 hour course and passing your state proctored examination is all that is required. (and or course $300,000 of liability Ins.)
So, don’t believe anyone that tells you that you need to pay them to join their group, It’s a scam. You don’t need to get ONLY their Continuing Education at an inflated price.
I’m by no means saying that there are not organization out there that are beneficial to Inspectors because they do continuing educating the industry.