How to protect from a flood of politically-motivated fake reviews?

Here is the situation: there is a new anti-war Documentary "Russians at War" that was released only to a small audience (200-300 people) during Venice Film Festival on Sept 5, 2024, not open to wide public, however this film received 20 1-star reviews immediately after that, Sept 6-8th. It is very likely that many people who wrote the reviews didn't see the film. These reviews use the same idea that the film was a Kremlin propaganda, even though the film is very critical to the state of the Russian Army (reviewers obviously don't know it, not seeing the film). So  reporting these fake reviews one by one to the IMDb might not be efficient not only for the reporting party but also for IMDb investigating all these numerous reports.

More seriously, same reviewers went after all 10 films on the IMDb that this director produced and massively added 1-star reviews to those films even though none of these films had anything to do with the Ukrainian-Russian war. How does the IMDb screen for and protects from such fake reviews? The director obviously doesn't have time to protect herself by reporting every single fake. If the IMDb can be so easily manipulated, what would happen to its reputation as an information source? I heard that there are mechanisms preventing the "revanche" and targeting biased postings but I wonder if IMDb uses them?