Actually it was floods of anti-Semitism directed at Jewish filmmakers. I flagged a few which were instantly taken down but I guess they couldn’t keep up.
You had all sorts of trolling (I witnessed more sex pervert posts than anti-Semitism), but the majority of the comments were productive. IMDb disregarded the wishes of the overwhelming majority of members who did not want it shut down. They had ample opportunity to put in anti-trolling safeguards, but refused to do it (such as banning accounts with multiple flagged posts and also putting a week or month delay in before permitting new accounts to post).