Guys, Saitama mentioning the "victim names association" refers to the "Hero Name Victims Association" group coming up to him to ask and join them on page 6. They formed a group because they're upset over the nicknames the Hero Association appointed to them (hence why they paid Caped Baldy a visit). Saitama thought they were the Neo Heroes at first, but apparently that has been completely cleared up off-screen since he calls them by their correct name (well, kinda) at the end.
In short, Saitama came to the right conclusion based on the invitation of the wrong (and absolutely hopelessly indescribably insignificant) group there.