Most people don't know who Eric is. I know of him and read his stuff early on before becoming atheist but I seriously doubt this is going to cause waves of negative publicity or backfire on them big time. He's not thar important in the grand scheme of things, just like I'm not, neither are any of as activists. The people in the cult don't know or care who we are. 99.9%of the world outside doesn't care biut us particularly either. So I'm not sure how this is going to make much impact outside of Eric and those adjacent to him.
I'm glad he's done what he's done. It's helped people. Maybe there's someone that follows his work that this pushes over the edge to leave the cult. If so, great! But people run around acting like this or that minor thing is going to bring the Borg down. Not even close. They got away with 1975 and overlapping generations. This is nothing.