I've noticed a similar issue with the Compared to You application, but not to the extent that you report.
This is simply a bug in the code for comparing your ratings against another user's ratings. In effect, the application is indicating that you did not rate any title lower than this other user. This may or may not be true.
It may help the IMDb technical staff to identify and correct the problem if you provide a link to your profile and the user of the ratings your compared.
Note: I am a long time user of IMDb and not an IMDb staff member.